KVM: Trivial: Use standard CR0 flags macros from asm/cpu-features.h

The kernel now has asm/cpu-features.h: use those macros instead of
inventing our own.

Also spell out definition of CR0_RESEVED_BITS (no code change) and fix typo.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index 23965aa..75faef4 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -158,7 +158,7 @@
 
 static int is_write_protection(struct kvm_vcpu *vcpu)
 {
-	return vcpu->cr0 & CR0_WP_MASK;
+	return vcpu->cr0 & X86_CR0_WP;
 }
 
 static int is_cpuid_PSE36(void)