KVM: MMU: Use kvm_mmu_sync_roots() in kvm_mmu_load()

No need to open-code this function.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

arch/x86/kvm/mmu.c

@@ -3764,9 +3764,7 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu)
 	if (r)
 		goto out;
 	r = mmu_alloc_roots(vcpu);
-	spin_lock(&vcpu->kvm->mmu_lock);
-	mmu_sync_roots(vcpu);
-	spin_unlock(&vcpu->kvm->mmu_lock);
+	kvm_mmu_sync_roots(vcpu);
 	if (r)
 		goto out;
 	/* set_cr3() should ensure TLB has been flushed */