kbuild: move -fzero-init-padding-bits=all to the top-level Makefile

The -fzero-init-padding-bits=all option is not a warning flag, so
defining it in scripts/Makefile.extrawarn is inconsistent.

Move it to the top-level Makefile for consistency.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>

Author: masahir0y

Makefile

@@ -928,6 +928,9 @@ KBUILD_CFLAGS	+= $(CC_AUTO_VAR_INIT_ZERO_ENABLER)
 endif
 endif
 
+# Explicitly clear padding bits during variable initialization
+KBUILD_CFLAGS += $(call cc-option,-fzero-init-padding-bits=all)
+
 # While VLAs have been removed, GCC produces unreachable stack probes
 # for the randomize_kstack_offset feature. Disable it for all compilers.
 KBUILD_CFLAGS	+= $(call cc-option, -fno-stack-clash-protection)

scripts/Makefile.extrawarn

@@ -82,9 +82,6 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=designated-init)
 # Warn if there is an enum types mismatch
 KBUILD_CFLAGS += $(call cc-option,-Wenum-conversion)
 
-# Explicitly clear padding bits during variable initialization
-KBUILD_CFLAGS += $(call cc-option,-fzero-init-padding-bits=all)
-
 KBUILD_CFLAGS += -Wextra
 KBUILD_CFLAGS += -Wunused