x86/kvm/hyper-v: remove stale evmcs_already_enabled check from nested_enable_evmcs()

In nested_enable_evmcs() evmcs_already_enabled check doesn't really do
anything: controls are already sanitized and we return '0' regardless.
Just drop the check.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/evmcs.c

@@ -350,17 +350,12 @@ int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 			uint16_t *vmcs_version)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	bool evmcs_already_enabled = vmx->nested.enlightened_vmcs_enabled;
 
 	vmx->nested.enlightened_vmcs_enabled = true;
 
 	if (vmcs_version)
 		*vmcs_version = nested_get_evmcs_version(vcpu);
 
-	/* We don't support disabling the feature for simplicity. */
-	if (evmcs_already_enabled)
-		return 0;
-
 	vmx->nested.msrs.pinbased_ctls_high &= ~EVMCS1_UNSUPPORTED_PINCTRL;
 	vmx->nested.msrs.entry_ctls_high &= ~EVMCS1_UNSUPPORTED_VMENTRY_CTRL;
 	vmx->nested.msrs.exit_ctls_high &= ~EVMCS1_UNSUPPORTED_VMEXIT_CTRL;