hwmon: (tmp102) Fix build warning

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

drivers/hwmon/tmp102.c:324:34: warning:
	‘tmp102_of_match’ defined but not used

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

drivers/hwmon/tmp102.c

@@ -303,7 +303,7 @@ static const struct i2c_device_id tmp102_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, tmp102_id);
 
-static const struct of_device_id tmp102_of_match[] = {
+static const struct of_device_id __maybe_unused tmp102_of_match[] = {
 	{ .compatible = "ti,tmp102" },
 	{ },
 };