ACPI / fan: remove no need check for device pointer

The device pointer will not be NULL in the PM callback and ACPI driver's
add/remove callback, so checking NULL for them isn't necessary.
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NZhang Rui <rui.zhang@intel.com>

drivers/acpi/fan.c

@@ -131,9 +131,6 @@ static int acpi_fan_add(struct acpi_device *device)
 	int result = 0;
 	struct thermal_cooling_device *cdev;
 
-	if (!device)
-		return -EINVAL;
-
 	strcpy(acpi_device_name(device), "Fan");
 	strcpy(acpi_device_class(device), ACPI_FAN_CLASS);
 
@@ -177,14 +174,7 @@ static int acpi_fan_add(struct acpi_device *device)
 
 static int acpi_fan_remove(struct acpi_device *device)
 {
-	struct thermal_cooling_device *cdev;
-
-	if (!device)
-		return -EINVAL;
-
-	cdev =  acpi_driver_data(device);
-	if (!cdev)
-		return -EINVAL;
+	struct thermal_cooling_device *cdev = acpi_driver_data(device);
 
 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
 	sysfs_remove_link(&cdev->device.kobj, "device");
@@ -196,9 +186,6 @@ static int acpi_fan_remove(struct acpi_device *device)
 #ifdef CONFIG_PM_SLEEP
 static int acpi_fan_suspend(struct device *dev)
 {
-	if (!dev)
-		return -EINVAL;
-
 	acpi_bus_set_power(to_acpi_device(dev)->handle, ACPI_STATE_D0);
 
 	return AE_OK;
@@ -208,9 +195,6 @@ static int acpi_fan_resume(struct device *dev)
 {
 	int result;
 
-	if (!dev)
-		return -EINVAL;
-
 	result = acpi_bus_update_power(to_acpi_device(dev)->handle, NULL);
 	if (result)
 		printk(KERN_ERR PREFIX "Error updating fan power state\n");