KVM: MMU: audit: fix vcpu's spte walking

After nested nested paging, it may using long mode to shadow 32/PAE paging
guest, so this patch fix it

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c
index bd2b1be7..dcca3e7 100644
--- a/arch/x86/kvm/mmu_audit.c
+++ b/arch/x86/kvm/mmu_audit.c
@@ -51,7 +51,7 @@
 	if (!VALID_PAGE(vcpu->arch.mmu.root_hpa))
 		return;
 
-	if (vcpu->arch.mmu.shadow_root_level == PT64_ROOT_LEVEL) {
+	if (vcpu->arch.mmu.root_level == PT64_ROOT_LEVEL) {
 		hpa_t root = vcpu->arch.mmu.root_hpa;
 
 		sp = page_header(root);