kernel: init: bss clear nocache memory as well

If something is tagged as nocache it didn't got cleared, which could
lead some weird behaviour where bss memory is non-zero.

Signed-off-by: Peter van der Perk <peter.vanderperk@nxp.com>

Author: PetervdPerk-NXP

kernel/init.c

@@ -247,6 +247,11 @@ void z_bss_zero(void)
 	z_early_memset(&__gcov_bss_start, 0,
 		       ((uintptr_t) &__gcov_bss_end - (uintptr_t) &__gcov_bss_start));
 #endif /* CONFIG_COVERAGE_GCOV */
+#ifdef CONFIG_NOCACHE_MEMORY
+z_early_memset(&_nocache_ram_start, 0,
+		   (uintptr_t) &_nocache_ram_end
+		   - (uintptr_t) &_nocache_ram_start);
+#endif
 }
 
 #ifdef CONFIG_LINKER_USE_BOOT_SECTION