KVM/MMU: Fix comment in walk_shadow_page_lockless_end()

kvm_commit_zap_page() has been renamed to kvm_mmu_commit_zap_page()
This patch is to fix the commit.
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu.c

@@ -899,7 +899,7 @@ static void walk_shadow_page_lockless_end(struct kvm_vcpu *vcpu)
 {
 	/*
 	 * Make sure the write to vcpu->mode is not reordered in front of
-	 * reads to sptes.  If it does, kvm_commit_zap_page() can see us
+	 * reads to sptes.  If it does, kvm_mmu_commit_zap_page() can see us
 	 * OUTSIDE_GUEST_MODE and proceed to free the shadow page table.
 	 */
 	smp_store_release(&vcpu->mode, OUTSIDE_GUEST_MODE);