MIPS: Fix build with C=1

When trying to compile the 3.1-rc10 kernel for my MIPS board with C=1
(sparse checking), the build fails early with the error:

	  CHK     include/linux/version.h
	  UPD     include/linux/version.h
	  CHK     include/generated/utsrelease.h
	  UPD     include/generated/utsrelease.h
	  Checking missing-syscalls for N32
	  CALL    scripts/checksyscalls.sh
	  Checking missing-syscalls for O32
	  CALL    scripts/checksyscalls.sh
	  CC      kernel/bounds.s
	  GEN     include/generated/bounds.h
	  CC      arch/mips/kernel/asm-offsets.s
	  GEN     include/generated/asm-offsets.h
	  CALL    scripts/checksyscalls.sh
	  HOSTCC  scripts/genksyms/genksyms.o
	  SHIPPED scripts/genksyms/lex.lex.c
	  SHIPPED scripts/genksyms/keywords.hash.c
	  SHIPPED scripts/genksyms/parse.tab.h
	  HOSTCC  scripts/genksyms/lex.lex.o
	  SHIPPED scripts/genksyms/parse.tab.c
	  HOSTCC  scripts/genksyms/parse.tab.o
	  HOSTLD  scripts/genksyms/genksyms
	/bin/sh: Syntax error: "(" unexpected
	make[3]: *** [scripts/mod/empty.o] Error 2
	make[2]: *** [scripts/mod] Error 2
	make[1]: *** [scripts] Error 2

It seems the shell chokes because sparse is called with command line
arguments such as:

	-D__INT8_C(c)='c'

Converting these to form:

	-D'__INT8_C(c)'='c'

seems to fix the problem.

[ralf@linux-mips.org: This affects builds with gcc 4.5 and newer.]
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/2827/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

@@ -226,7 +226,7 @@ LDFLAGS			+= -m $(ld-emul)
 ifdef CONFIG_MIPS
 CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -xc /dev/null | \
 	egrep -vw '__GNUC_(|MINOR_|PATCHLEVEL_)_' | \
-	sed -e 's/^\#define /-D/' -e "s/ /='/" -e "s/$$/'/")
+	sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/")
 ifdef CONFIG_64BIT
 CHECKFLAGS		+= -m64
 endif