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/oprofile/Makefile b/arch/mips/oprofile/Makefile
index 02cc65e..4b9d704 100644
--- a/arch/mips/oprofile/Makefile
+++ b/arch/mips/oprofile/Makefile
@@ -1,4 +1,4 @@
-EXTRA_CFLAGS := -Werror
+ccflags-y := -Werror
 
 obj-$(CONFIG_OPROFILE) += oprofile.o