platform/x86: asus-wireless: Fix uninitialized symbol usage

'ret' will not be initialized if acpi_evaluate_integer() returns through
an error path, so it should not be used in this case. This fixes the
following Smatch static analyser error:

 drivers/platform/x86/asus-wireless.c:76 asus_wireless_method() error:
                                                     uninitialized symbol 'ret'.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: João Paulo Rechi Vita <jprvita@endlessm.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/x86/asus-wireless.c

@@ -52,13 +52,12 @@ static const struct acpi_device_id device_ids[] = {
 };
 MODULE_DEVICE_TABLE(acpi, device_ids);
 
-static u64 asus_wireless_method(acpi_handle handle, const char *method,
-				int param)
+static acpi_status asus_wireless_method(acpi_handle handle, const char *method,
+					int param, u64 *ret)
 {
 	struct acpi_object_list p;
 	union acpi_object obj;
 	acpi_status s;
-	u64 ret;
 
 	acpi_handle_debug(handle, "Evaluating method %s, parameter %#x\n",
 			  method, param);
@@ -67,24 +66,27 @@ static u64 asus_wireless_method(acpi_handle handle, const char *method,
 	p.count = 1;
 	p.pointer = &obj;
 
-	s = acpi_evaluate_integer(handle, (acpi_string) method, &p, &ret);
+	s = acpi_evaluate_integer(handle, (acpi_string) method, &p, ret);
 	if (ACPI_FAILURE(s))
 		acpi_handle_err(handle,
 				"Failed to eval method %s, param %#x (%d)\n",
 				method, param, s);
-	acpi_handle_debug(handle, "%s returned %#llx\n", method, ret);
-	return ret;
+	else
+		acpi_handle_debug(handle, "%s returned %#llx\n", method, *ret);
+
+	return s;
 }
 
 static enum led_brightness led_state_get(struct led_classdev *led)
 {
 	struct asus_wireless_data *data;
-	int s;
+	acpi_status s;
+	u64 ret;
 
 	data = container_of(led, struct asus_wireless_data, led);
 	s = asus_wireless_method(acpi_device_handle(data->adev), "HSWC",
-				 data->hswc_params->status);
-	if (s == data->hswc_params->on)
+				 data->hswc_params->status, &ret);
+	if (ACPI_SUCCESS(s) && ret == data->hswc_params->on)
 		return LED_FULL;
 	return LED_OFF;
 }
@@ -92,10 +94,11 @@ static enum led_brightness led_state_get(struct led_classdev *led)
 static void led_state_update(struct work_struct *work)
 {
 	struct asus_wireless_data *data;
+	u64 ret;
 
 	data = container_of(work, struct asus_wireless_data, led_work);
 	asus_wireless_method(acpi_device_handle(data->adev), "HSWC",
-			     data->led_state);
+			     data->led_state, &ret);
 }
 
 static void led_state_set(struct led_classdev *led, enum led_brightness value)