boards: cxd56xx: Fix the build error in cxd56_crashdump.c

Summary:
- This commit fixes the build error in cxd56_crashdump.c
  regressed by https://github.com/apache/nuttx/pull/7707

Impact:
- None

Tesing:
- Tested with spresense:wifi

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

boards/arm/cxd56xx/common/src/cxd56_crashdump.c

@@ -238,5 +238,7 @@ void board_crashdump(uintptr_t currentsp, void *tcb,
 exit:
 #if defined(CONFIG_CXD56_RESET_ON_CRASH)
   board_reset_on_crash();
+#else
+  return;
 #endif
 }