odroidc1: fix u-boot build on trixie (GCC 14 promoted-to-error warnings)

CI "Build All Artifacts" fails uboot-odroidc1-current on the trixie host. The
2011-era hardkernel Amlogic u-boot (odroidc-v2011.03) hits a pile of warnings
that GCC 14 now treats as hard errors by default:

  board.c:30: -Wint-conversion (pointer from integer)
  board.c:512: implicit declaration of 'get_dev_by_name'
  board.c:739: implicit declaration of 'vpu_probe'
  bootm.c:281: implicit declaration of 'amlogic_gpio_direction_output'
  gpio.c:332/333: implicit declaration of 'malloc' / 'free'
  gpio.c:850+: -Wincompatible-pointer-types (function pointer mismatches)

It built on noble/GCC 13. Add a post_config_uboot_target hook that appends the
four -Wno-error= flags to uboot_cflags_array (same mechanism as the odroidxu4
and rockchip-rv1106 GCC-downgrade hooks), including -Wno-error=int-conversion
for the pervasive pointer<->integer cases. ARCH=armhf, so int and pointer are
the same width and those conversions are benign; the implicit-decl symbols
resolve at link time. Keeps the known-good hardkernel boot chain unchanged.

Signed-off-by: Igor Pecovnik <igor@armbian.com>

Author: igorpecovnik

config/boards/odroidc1.conf

@@ -26,3 +26,20 @@ write_uboot_platform() {
 	dd if=$1/u-boot.bin of=$2 bs=512 seek=64 conv=fsync > /dev/null 2>&1
 	dd if=/dev/zero of=$2 seek=1024 count=32 bs=512 conv=fsync > /dev/null 2>&1
 }
+
+# GCC 14 (trixie host) promotes -Wint-conversion, -Wimplicit-function-declaration,
+# -Wimplicit-int and -Wincompatible-pointer-types from warning to hard error. This
+# 2011-era hardkernel Amlogic u-boot (odroidc-v2011.03) trips on all of them
+# (board.c / gpio.c / bootm.c: get_dev_by_name, vpu_probe, amlogic_gpio_*, malloc,
+# pointer-from-integer, ...). It built on noble/GCC 13; downgrade back to warnings
+# so it builds on trixie. ARCH=armhf, so the int<->pointer conversions are
+# same-width and benign.
+function post_config_uboot_target__odroidc1_downgrade_gcc14_errors() {
+	uboot_cflags_array+=(
+		"-Wno-error=implicit-function-declaration"
+		"-Wno-error=implicit-int"
+		"-Wno-error=int-conversion"
+		"-Wno-error=incompatible-pointer-types"
+	)
+	return 0
+}