net: rfkill: convert net/rfkill/* to use module_platform_driver()

This patch converts the drivers in net/rfkill/* to use the
module_platform_driver() macro which makes the code smaller and a bit
simpler.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Antonio Ospite <ospite@studenti.unina.it>
Cc: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/rfkill/rfkill-gpio.c b/net/rfkill/rfkill-gpio.c
index 128677d..ca355e7 100644
--- a/net/rfkill/rfkill-gpio.c
+++ b/net/rfkill/rfkill-gpio.c
@@ -220,18 +220,7 @@
 	},
 };
 
-static int __init rfkill_gpio_init(void)
-{
-	return platform_driver_register(&rfkill_gpio_driver);
-}
-
-static void __exit rfkill_gpio_exit(void)
-{
-	platform_driver_unregister(&rfkill_gpio_driver);
-}
-
-module_init(rfkill_gpio_init);
-module_exit(rfkill_gpio_exit);
+module_platform_driver(rfkill_gpio_driver);
 
 MODULE_DESCRIPTION("gpio rfkill");
 MODULE_AUTHOR("NVIDIA");