char: hw_random: convert drivers/char/hw_random/* to use module_platform_driver()

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

Cc: David S. Miller <davem@davemloft.net>
Cc: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Alexander Clouter <alex@digriz.org.uk>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: David Daney <david.daney@cavium.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c
index 241df2e..f518b99 100644
--- a/drivers/char/hw_random/atmel-rng.c
+++ b/drivers/char/hw_random/atmel-rng.c
@@ -141,17 +141,7 @@
 	},
 };
 
-static int __init atmel_trng_init(void)
-{
-	return platform_driver_register(&atmel_trng_driver);
-}
-module_init(atmel_trng_init);
-
-static void __exit atmel_trng_exit(void)
-{
-	platform_driver_unregister(&atmel_trng_driver);
-}
-module_exit(atmel_trng_exit);
+module_platform_driver(atmel_trng_driver);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");