mmc: convert drivers/mmc/host/* to use module_platform_driver()

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

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Acked-by: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Acked-by: David Brown <davidb@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
diff --git a/drivers/mmc/host/sdhci-cns3xxx.c b/drivers/mmc/host/sdhci-cns3xxx.c
index b4257e7..28a8708 100644
--- a/drivers/mmc/host/sdhci-cns3xxx.c
+++ b/drivers/mmc/host/sdhci-cns3xxx.c
@@ -115,17 +115,7 @@
 	.remove		= __devexit_p(sdhci_cns3xxx_remove),
 };
 
-static int __init sdhci_cns3xxx_init(void)
-{
-	return platform_driver_register(&sdhci_cns3xxx_driver);
-}
-module_init(sdhci_cns3xxx_init);
-
-static void __exit sdhci_cns3xxx_exit(void)
-{
-	platform_driver_unregister(&sdhci_cns3xxx_driver);
-}
-module_exit(sdhci_cns3xxx_exit);
+module_platform_driver(sdhci_cns3xxx_driver);
 
 MODULE_DESCRIPTION("SDHCI driver for CNS3xxx");
 MODULE_AUTHOR("Scott Shu, "