hwmon: (pmbus/ir38064) Mark ir38064_of_match as __maybe_unused

If CONFIG_PM is not enabled, the following warning is reported.

drivers/hwmon/pmbus/ir38064.c:54:34: warning:
	unused variable 'ir38064_of_match'

Mark it as __maybe_unused.
Reported-by: kernel test robot <lkp@intel.com>
Cc: Arthur Heymans <arthur.heymans@9elements.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/ir38064.c

@@ -62,7 +62,7 @@ static const struct i2c_device_id ir38064_id[] = {
 
 MODULE_DEVICE_TABLE(i2c, ir38064_id);
 
-static const struct of_device_id ir38064_of_match[] = {
+static const struct of_device_id __maybe_unused ir38064_of_match[] = {
 	{ .compatible = "infineon,ir38060" },
 	{ .compatible = "infineon,ir38064" },
 	{ .compatible = "infineon,ir38164" },