kvm: vmx: Fix typos comment in __loaded_vmcs_clear()

Fix a comment documenting the memory barrier related to clearing a
loaded_vmcs; loaded_vmcs tracks the host CPU the VMCS is loaded on via
the field 'cpu', it doesn't have a 'vcpu' field.
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Message-Id: <20220222104029.70129-1-flyingpeng@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -640,10 +640,10 @@ static void __loaded_vmcs_clear(void *arg)
 
 	/*
 	 * Ensure all writes to loaded_vmcs, including deleting it from its
-	 * current percpu list, complete before setting loaded_vmcs->vcpu to
-	 * -1, otherwise a different cpu can see vcpu == -1 first and add
-	 * loaded_vmcs to its percpu list before it's deleted from this cpu's
-	 * list. Pairs with the smp_rmb() in vmx_vcpu_load_vmcs().
+	 * current percpu list, complete before setting loaded_vmcs->cpu to
+	 * -1, otherwise a different cpu can see loaded_vmcs->cpu == -1 first
+	 * and add loaded_vmcs to its percpu list before it's deleted from this
+	 * cpu's list. Pairs with the smp_rmb() in vmx_vcpu_load_vmcs().
 	 */
 	smp_wmb();