hwmon: (lm75) Fix build warning

If CONFIG_OF is not enabled, the following build warning is observed.

drivers/hwmon/lm75.c:446:34: warning:
	‘lm75_of_match’ defined but not used

Mark lm75_of_match as __maybe_unused to fix the problem.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/lm75.c

@@ -419,7 +419,7 @@ static const struct i2c_device_id lm75_ids[] = {
 };
 MODULE_DEVICE_TABLE(i2c, lm75_ids);
 
-static const struct of_device_id lm75_of_match[] = {
+static const struct of_device_id __maybe_unused lm75_of_match[] = {
 	{
 		.compatible = "adi,adt75",
 		.data = (void *)adt75