mfd: tps6507x: Make of_device_id array const

Make of_device_id array const, because all OF functions
handle it as const.

Signed-off-by: Jingoo Han <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/tps6507x.c

···
 MODULE_DEVICE_TABLE(i2c, tps6507x_i2c_id);
 
 #ifdef CONFIG_OF
-static struct of_device_id tps6507x_of_match[] = {
+static const struct of_device_id tps6507x_of_match[] = {
 	{.compatible = "ti,tps6507x", },
 	{},
 };