wifi: shell: Disable POSIX_MULTI_PROCESS in config

[SHEL-4053] The POSIX_MULTI_PROCESS is effecting the
Throughput numbers, disable it in config.

Signed-off-by: Kapil Bhatt <kapil.bhatt@nordicsemi.no>

Author: kapbh

samples/wifi/shell/overlay-zperf.conf

@@ -37,3 +37,7 @@ CONFIG_NRF70_UTIL=y
 
 # Disable rate limiting to avoid log flooding (default is drop)
 CONFIG_LOG_RATELIMIT=n
+
+# Disabled to avoid pulling in CONFIG_THREAD_RUNTIME_STATS, whose
+# per-context-switch overhead reduces throughput.
+CONFIG_POSIX_MULTI_PROCESS=n

samples/wifi/throughput/prj.conf

@@ -78,6 +78,10 @@ CONFIG_POSIX_TIMERS=y
 CONFIG_DATE_SHELL=y
 CONFIG_NET_CONFIG_AUTO_INIT=n
 
+# Disabled to avoid pulling in CONFIG_THREAD_RUNTIME_STATS, whose
+# per-context-switch overhead reduces throughput.
+CONFIG_POSIX_MULTI_PROCESS=n
+
 CONFIG_WIFI_CREDENTIALS=y
 CONFIG_FLASH=y
 CONFIG_FLASH_PAGE_LAYOUT=y