Kernel: gcov: Makefile: Use proper ccflag flag in Makefile

Use the ccflags-y flag instead of EXTRA_CFLAGS because EXTRA_CFLAGS is deprecated and should now be switched. According to (documentation/kbuild/makefiles.txt)

---
 kernel/gcov/Makefile |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

index 3f76100..e97ca59 100644
@@ -1,3 +1,3 @@
-EXTRA_CFLAGS := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
+ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
 
 obj-$(CONFIG_GCOV_KERNEL) := base.o fs.o gcc_3_4.o

1.7.4.rc2

Thanks.