KVM: MMU: remove mmu_seq verification on pte update path

The mmu_seq verification can be removed since we get the pfn in the
protection of mmu_lock.

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index c639779..74f8567 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -325,7 +325,7 @@
 }
 
 static void FNAME(update_pte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
-			      u64 *spte, const void *pte, unsigned long mmu_seq)
+			      u64 *spte, const void *pte)
 {
 	pt_element_t gpte;
 	unsigned pte_access;
@@ -342,8 +342,6 @@
 		kvm_release_pfn_clean(pfn);
 		return;
 	}
-	if (mmu_notifier_retry(vcpu, mmu_seq))
-		return;
 
 	/*
 	 * we call mmu_set_spte() with host_writable = true because that