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>

arch/x86/kvm/Makefile

 
-EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm
+ccflags-y += -Ivirt/kvm -Iarch/x86/kvm
 
 CFLAGS_x86.o := -I.
 CFLAGS_svm.o := -I.