kbuild: remove cc-option switch from -Wframe-larger-than=

This CONFIG option was added by commit 35bb5b1e ("Add option to
enable -Wframe-larger-than= on gcc 4.4"). At that time, the cc-option
check was needed.

According to Documentation/process/changes.rst, the current minimal
supported version of GCC is 4.6, so you can assume GCC supports it.
Clang supports it as well.

Remove the cc-option switch and redundant comments.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Reviewed-by: NNathan Chancellor <natechancellor@gmail.com>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>

Makefile

@@ -729,7 +729,7 @@ KBUILD_CFLAGS += $(call cc-option,-fno-reorder-blocks,) \
 endif
 
 ifneq ($(CONFIG_FRAME_WARN),0)
-KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN})
+KBUILD_CFLAGS += -Wframe-larger-than=$(CONFIG_FRAME_WARN)
 endif
 
 stackp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector

lib/Kconfig.debug

@@ -266,7 +266,7 @@ config ENABLE_MUST_CHECK
 	  attribute warn_unused_result" messages.
 
 config FRAME_WARN
-	int "Warn for stack frames larger than (needs gcc 4.4)"
+	int "Warn for stack frames larger than"
 	range 0 8192
 	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
 	default 1280 if (!64BIT && PARISC)
@@ -276,7 +276,6 @@ config FRAME_WARN
 	  Tell gcc to warn at build time for stack frames larger than this.
 	  Setting this too low will cause a lot of warnings.
 	  Setting it to 0 disables the warning.
-	  Requires gcc 4.4
 
 config STRIP_ASM_SYMS
 	bool "Strip assembler-generated symbols during link"