mfd: max8907: Make of_device_id array const

Array of struct of_device_id may be be const as expected by
of_match_table field.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/max8907.c

···
 }
 
 #ifdef CONFIG_OF
-static struct of_device_id max8907_of_match[] = {
+static const struct of_device_id max8907_of_match[] = {
 	{ .compatible = "maxim,max8907" },
 	{ },
 };