gpio-backlight: Discover driver during boot time

The gpio-backlight driver seems to be missing the
MODULE_DEVICE_TABLE line which is preventing it from
being modprobed during boot time even if the
gpio-backlight device exists.

This seems to be a bug and this patch attempts to
fix that.

Signed-off-by: Arun Bharadwaj <[e-mail]>
Signed-off-by: Ash Charles <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/video/backlight/gpio_backlight.c

···
 	{ .compatible = "gpio-backlight" },
 	{ /* sentinel */ }
 };
+
+MODULE_DEVICE_TABLE(of, gpio_backlight_of_match);
 #endif
 
 static struct platform_driver gpio_backlight_driver = {