MIPS: Loongson{2ef,64}: Wrap -mno-branch-likely with cc-option

This flag is not supported by clang, which results in a warning:

  clang-14: warning: argument unused during compilation: '-mno-branch-likely' [-Wunused-command-line-argument]

This breaks cc-option, which adds -Werror to make this warning fatal and
catch flags that are not supported.

Wrap this flag in cc-option so that it does not cause cc-option to fail,
which can cause randconfigs to be really noisy, due to warnings not
getting disabled that should be.

Additionally, move the cc-option check to Kconfig so that the check is
done at configuration time, rather than build time, as builds with no
configuration change will be quicker because the cc-option call will not
need to happen in those instances.
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/Kconfig

@@ -3202,6 +3202,10 @@ config MIPS32_N32
 
 	  If unsure, say N.
 
+config CC_HAS_MNO_BRANCH_LIKELY
+	def_bool y
+	depends on $(cc-option,-mno-branch-likely)
+
 menu "Power management options"
 
 config ARCH_HIBERNATION_POSSIBLE

arch/mips/loongson2ef/Platform

@@ -41,6 +41,7 @@ cflags-y += $(call cc-option,-mno-loongson-mmi)
 # Loongson Machines' Support
 #
 
-cflags-$(CONFIG_MACH_LOONGSON2EF) += -I$(srctree)/arch/mips/include/asm/mach-loongson2ef -mno-branch-likely
+cflags-$(CONFIG_MACH_LOONGSON2EF) += -I$(srctree)/arch/mips/include/asm/mach-loongson2ef
+cflags-$(CONFIG_CC_HAS_MNO_BRANCH_LIKELY) += -mno-branch-likely
 load-$(CONFIG_LEMOTE_FULOONG2E) += 0xffffffff80100000
 load-$(CONFIG_LEMOTE_MACH2F) += 0xffffffff80200000

arch/mips/loongson64/Platform

@@ -18,5 +18,6 @@ cflags-y += $(call cc-option,-mno-loongson-mmi)
 # Loongson Machines' Support
 #
 
-cflags-$(CONFIG_MACH_LOONGSON64) += -I$(srctree)/arch/mips/include/asm/mach-loongson64 -mno-branch-likely
+cflags-$(CONFIG_MACH_LOONGSON64) += -I$(srctree)/arch/mips/include/asm/mach-loongson64
+cflags-$(CONFIG_CC_HAS_MNO_BRANCH_LIKELY) += -mno-branch-likely
 load-$(CONFIG_CPU_LOONGSON64) += 0xffffffff80200000