kbuild: Cache a few more calls to the compiler

These are a few stragglers that I left out of the original patch to
cache calls to the C compiler ("kbuild: Add a cache for generated
variables") because they bleed out into the main Makefile and thus
uglify things a little bit.  The idea is the same here, though.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

Makefile

@@ -638,7 +638,7 @@ KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
 KBUILD_CFLAGS	+= $(call cc-option,--param=allow-store-data-races=0)
 
 # check for 'asm goto'
-ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
+ifeq ($(call shell-cached,$(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC) $(KBUILD_CFLAGS)), y)
 	KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
 	KBUILD_AFLAGS += -DCC_HAVE_ASM_GOTO
 endif
@@ -774,7 +774,7 @@ KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
-NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
+NOSTDINC_FLAGS += -nostdinc -isystem $(call shell-cached,$(CC) -print-file-name=include)
 CHECKFLAGS     += $(NOSTDINC_FLAGS)
 
 # warn about C99 declaration after statement