!sys/types.h: change time_t and clock_t to int64_t to align with other OSes

POSIX leaves the signedness of time_t and clock_t unspecified, but
mainstream implementations (Linux glibc/musl, the BSDs, macOS, RTEMS,
Zephyr's POSIX layer, Windows _time64) expose time_t as signed 64-bit.
NuttX has historically used uint64_t only because it was tied to the
CONFIG_SYSTEM_TIME64 knob; with that gone, switch:

  time_t   : uint64_t  -> int64_t
  clock_t  : uint64_t  -> int64_t
  CLOCK_MAX: UINT64_MAX -> INT64_MAX

This lets (time_t)-1 sentinels, negative tick deltas, and host-side
headers behave as on every other POSIX system without source churn.

Headers updated:
  - include/sys/types.h, include/limits.h, include/nuttx/clock.h
  - include/nuttx/fs/hostfs.h (nuttx_time_t alias)
  - include/nuttx/{mqueue.h,wdog.h,wqueue.h,timers/clkcnt.h}

Because clock_t is now signed 64-bit, the NuttX-internal sclock_t
alias becomes redundant: every sclock_t/SCLOCK_MAX use is folded
back to clock_t/CLOCK_MAX (notably in sched/wdog, sched/mqueue,
sched/sched, sched/clock, sched/timer, libs/libc/time, fs/vfs and
the drivers/arch consumers below).

Tick/period constants (NSEC_PER_SEC, USEC_PER_SEC, MSEC_PER_SEC,
SEC_PER_MIN, ...) in include/nuttx/clock.h are retyped from "long"
literals to INT64_C(...) so that 64-bit arithmetic no longer
depends on the host's long width.

Strip now-redundant (time_t)/(clock_t)/(unsigned long) casts and
unsigned-only branches across the tree:
  - arch RTC / oneshot / tickless lowerhalfs:
      arm: cxd56xx, efm32, imxrt, lc823450, max326xx, sam34, sama5,
           samd5e5, samv7, stm32, stm32f7, stm32h7, stm32l4, stm32wb,
           xmc4
      mips: pic32mz       sparc: bm3803       x86_64: intel64
      risc-v/xtensa: espressif (esp_i2c[_slave], esp_rtc,
           esp32c3{_i2c,_rtc,_wifi_adapter}, esp32{,s2,s3}_*),
           mpfs_perf
  - drivers: audio/tone, input/aw86225, power/pm/{activity,
           stability}_governor, rpmsg/rpmsg_ping,
           timers/{ds3231,mcp794xx,pcf85263,rx8010},
           wireless/ieee80211/bcm43xxx, wireless/spirit/spirit_spi
  - core: fs/vfs/{fs_poll,fs_timerfd}, mm/iob/iob_alloc,
          libs/libc/{netdb/lib_dnscache,time/{lib_calendar2utc,
          lib_time}}, net/icmp/icmp_pmtu, net/icmpv6/icmpv6_pmtu,
          net/ipfrag, net/tcp/{tcp.h,tcp_timer},
          net/utils/net_snoop, net/mld/mld_query (drop the now-dead
          mld_mrc2mrd helper since signed math handles it directly),
          sched/clock/{clock,clock_initialize},
          sched/sched/{sched_profil,sched_setparam,sched_setscheduler},
          sched/pthread/pthread_create,
          sched/wdog/{wd_gettime,wd_start,wdog.h},
          sched/timer/timer_gettime, sched/mqueue/*

Flip the few in-tree printf format strings that assumed an
unsigned 64-bit tv_sec:
  * drivers/rpmsg/rpmsg_ping.c                       PRIu64 -> PRId64
  * arch/xtensa/src/esp32{,s2,s3}/esp32*_oneshot_lowerhalf.c
                                          PRIu32 (already wrong) -> PRId64

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

Author: xiaoxiang781216

arch/arm/src/cxd56xx/cxd56_rtc.c

@@ -394,7 +394,7 @@ time_t up_rtc_time(void)
   count += g_rtc_save->offset;
   count >>= 15; /* convert to 1sec resolution */
 
-  return (time_t)count / CONFIG_RTC_FREQUENCY;
+  return count / CONFIG_RTC_FREQUENCY;
 }
 #endif
 

arch/arm/src/efm32/efm32_rtc_burtc.c

@@ -398,7 +398,7 @@ int up_rtc_initialize(void)
 #ifndef CONFIG_RTC_HIRES
 time_t up_rtc_time(void)
 {
-  return (time_t)efm32_get_burtc_tick() / CONFIG_RTC_FREQUENCY;
+  return efm32_get_burtc_tick() / CONFIG_RTC_FREQUENCY;
 }
 #endif
 

arch/arm/src/imxrt/imxrt_rtc_lowerhalf.c

@@ -463,7 +463,7 @@ static int imxrt_rdalarm(struct rtc_lowerhalf_s *lower,
 
       /* Get the current alarm setting in seconds */
 
-      alarm = (time_t)imxrt_hprtc_getalarm();
+      alarm = imxrt_hprtc_getalarm();
 
       /* Convert the one second epoch time to a struct tm */
 

arch/arm/src/lc823450/lc823450_rtc.c

@@ -173,7 +173,7 @@ static void tm_divider(struct tm *tm, int divn, int divm)
 {
   time_t tt;
   tt = timegm(tm);
-  tt = (time_t) ((uint64_t)tt * divn / divm);
+  tt = tt * divn / divm;
   gmtime_r(&tt, tm);
 }
 #endif /* CONFIG_RTC_DIV */

arch/arm/src/lc823450/lc823450_timer.c

@@ -724,8 +724,8 @@ int up_rtc_gettime(struct timespec *tp)
 
   /* And return the result to the caller. */
 
-  tp->tv_sec  = (time_t)secs;
-  tp->tv_nsec = (long)nsecs;
+  tp->tv_sec  = secs;
+  tp->tv_nsec = nsecs;
 
   tmrinfo("Returning tp=(%d,%d)\n", (int)tp->tv_sec, (int)tp->tv_nsec);
   return OK;

arch/arm/src/max326xx/common/max326_rtc_lowerhalf.c

@@ -581,7 +581,7 @@ static int max326_rdalarm(struct rtc_lowerhalf_s *lower,
         {
           /* Extract integer seconds from the b32_t value */
 
-          time_t sec = (time_t)(b32toi(ftime));
+          time_t sec = b32toi(ftime);
 
           /* Convert to struct rtc_time (aka struct tm) */
 

arch/arm/src/sam34/sam4cm_oneshot.c

@@ -496,8 +496,8 @@ int sam_oneshot_cancel(struct sam_oneshot_s *oneshot,
           sec         = usec / USEC_PER_SEC;
           nsec        = ((usec) - (sec * USEC_PER_SEC)) * NSEC_PER_USEC;
 
-          ts->tv_sec  = (time_t)sec;
-          ts->tv_nsec = (unsigned long)nsec;
+          ts->tv_sec  = sec;
+          ts->tv_nsec = nsec;
         }
 
       tmrinfo("remaining (%lu, %lu)\n",

arch/arm/src/sam34/sam4cm_oneshot_lowerhalf.c

@@ -152,8 +152,8 @@ static int sam_max_delay(struct oneshot_lowerhalf_s *lower,
       uint64_t sec = usecs / 1000000;
       usecs -= 1000000 * sec;
 
-      ts->tv_sec  = (time_t)sec;
-      ts->tv_nsec = (long)(usecs * 1000);
+      ts->tv_sec  = sec;
+      ts->tv_nsec = usecs * 1000;
     }
 
   return ret;

arch/arm/src/sama5/sam_oneshot.c

@@ -507,8 +507,8 @@ int sam_oneshot_cancel(struct sam_oneshot_s *oneshot,
           sec         = usec / USEC_PER_SEC;
           nsec        = ((usec) - (sec * USEC_PER_SEC)) * NSEC_PER_USEC;
 
-          ts->tv_sec  = (time_t)sec;
-          ts->tv_nsec = (unsigned long)nsec;
+          ts->tv_sec  = sec;
+          ts->tv_nsec = nsec;
         }
 
       tmrinfo("remaining (%lu, %lu)\n",

arch/arm/src/sama5/sam_oneshot_lowerhalf.c

@@ -154,8 +154,8 @@ static int sam_max_delay(struct oneshot_lowerhalf_s *lower,
       uint64_t sec = usecs / 1000000;
       usecs -= 1000000 * sec;
 
-      ts->tv_sec  = (time_t)sec;
-      ts->tv_nsec = (long)(usecs * 1000);
+      ts->tv_sec  = sec;
+      ts->tv_nsec = usecs * 1000;
     }
 
   return ret;