MIPS: Loongson: Fix build error when make modules_install

After commit 0e96ea5c ("MIPS: Loongson64: Clean up use of
cc-ifversion") we get a build error when make modules_install:

cc1: error: '-mloongson-mmi' must be used with '-mhard-float'

The reason is when make modules_install, 'call cc-option' doesn't work
in $(KBUILD_CFLAGS) of 'CHECKFLAGS'. Then there is no -mno-loongson-mmi
applied and -march=loongson3a enable MMI instructions.

To be detail, the error message comes from the CHECKFLAGS invocation of
$(CC) but it has no impact on the final result of make modules_install,
it is purely a cosmetic issue. The error occurs because cc-option is
defined in scripts/Makefile.compiler, which is not included in Makefile
when running 'make modules_install', as install targets are not supposed
to require the compiler; see commit 805b2e1d ("kbuild: include
Makefile.compiler only when compiler is needed"). As a result, the call
to check for '-mno-loongson-mmi' just never happens.

Fix this by partially reverting to the old logic, use 'call cc-option'
to conditionally apply -march=loongson3a and -march=mips64r2.

By the way, Loongson-2E/2F is also broken in commit 13ceb48b
("MIPS: Loongson2ef: Remove unnecessary {as,cc}-option calls") so fix it
together.

Fixes: 13ceb48b ("MIPS: Loongson2ef: Remove unnecessary {as,cc}-option calls")
Fixes: 0e96ea5c ("MIPS: Loongson64: Clean up use of cc-ifversion")
Cc: stable@vger.kernel.org
Cc: Feiyang Chen <chenfeiyang@loongson.cn>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/Makefile

@@ -181,16 +181,12 @@ endif
 cflags-$(CONFIG_CAVIUM_CN63XXP1) += -Wa,-mfix-cn63xxp1
 cflags-$(CONFIG_CPU_BMIPS)	+= -march=mips32 -Wa,-mips32 -Wa,--trap
 
-cflags-$(CONFIG_CPU_LOONGSON2E) += -march=loongson2e -Wa,--trap
-cflags-$(CONFIG_CPU_LOONGSON2F) += -march=loongson2f -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON2E) += $(call cc-option,-march=loongson2e) -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON2F) += $(call cc-option,-march=loongson2f) -Wa,--trap
+cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-march=loongson3a,-march=mips64r2) -Wa,--trap
 # Some -march= flags enable MMI instructions, and GCC complains about that
 # support being enabled alongside -msoft-float. Thus explicitly disable MMI.
 cflags-$(CONFIG_CPU_LOONGSON2EF) += $(call cc-option,-mno-loongson-mmi)
-ifdef CONFIG_CPU_LOONGSON64
-cflags-$(CONFIG_CPU_LOONGSON64)	+= -Wa,--trap
-cflags-$(CONFIG_CC_IS_GCC) += -march=loongson3a
-cflags-$(CONFIG_CC_IS_CLANG) += -march=mips64r2
-endif
 cflags-$(CONFIG_CPU_LOONGSON64) += $(call cc-option,-mno-loongson-mmi)
 
 cflags-$(CONFIG_CPU_R4000_WORKAROUNDS)	+= $(call cc-option,-mfix-r4000,)