KVM: x86: Makefile clean up

Changed makefile to use the ccflags-y option instead of EXTRA_CFLAGS.

Signed-off-by: Tracey Dent <tdent48227@gmail.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index c53bf19..f15501f43 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -1,5 +1,5 @@
 
-EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm
+ccflags-y += -Ivirt/kvm -Iarch/x86/kvm
 
 CFLAGS_x86.o := -I.
 CFLAGS_svm.o := -I.