mips: change to new flag variable

Replace EXTRA_CFLAGS with ccflags-y.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 7c1102e..ac1d5b6 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -286,11 +286,11 @@
 archprepare:
 ifdef CONFIG_MIPS32_N32
 	@echo '  Checking missing-syscalls for N32'
-	$(Q)$(MAKE) $(build)=. missing-syscalls EXTRA_CFLAGS="-mabi=n32"
+	$(Q)$(MAKE) $(build)=. missing-syscalls ccflags-y="-mabi=n32"
 endif
 ifdef CONFIG_MIPS32_O32
 	@echo '  Checking missing-syscalls for O32'
-	$(Q)$(MAKE) $(build)=. missing-syscalls EXTRA_CFLAGS="-mabi=32"
+	$(Q)$(MAKE) $(build)=. missing-syscalls ccflags-y="-mabi=32"
 endif
 
 install: