[MIPS] SB1: Check for -mno-sched-prolog if building corelis debug kernel.

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

@@ -108,7 +108,8 @@ MODFLAGS			+= -mlong-calls
 cflags-$(CONFIG_CPU_BIG_ENDIAN)		+= $(shell $(CC) -dumpmachine |grep -q 'mips.*el-.*' && echo -EB)
 cflags-$(CONFIG_CPU_LITTLE_ENDIAN)	+= $(shell $(CC) -dumpmachine |grep -q 'mips.*el-.*' || echo -EL)
 
-cflags-$(CONFIG_SB1XXX_CORELIS)	+= -mno-sched-prolog -fno-omit-frame-pointer
+cflags-$(CONFIG_SB1XXX_CORELIS)	+= $(call cc-option,-mno-sched-prolog) \
+				   -fno-omit-frame-pointer
 
 #
 # Use: $(call set_gccflags,<cpu0>,<isa0>,<cpu1>,<isa1>,<isa2>)