rtc: rv3032: quiet maybe-unused variable warning

When CONFIG_OF is disabled then the matching table is not referenced.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210202112219.3610853-17-alexandre.belloni@bootlin.com

drivers/rtc/rtc-rv3032.c

@@ -906,7 +906,7 @@ static int rv3032_probe(struct i2c_client *client)
 	return 0;
 }
 
-static const struct of_device_id rv3032_of_match[] = {
+static const __maybe_unused struct of_device_id rv3032_of_match[] = {
 	{ .compatible = "microcrystal,rv3032", },
 	{ }
 };