mtd: convert drivers/mtd/* to use module_platform_driver()

This patch converts the drivers in drivers/mtd/* 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: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
index 9eb7f87..90d6016 100644
--- a/drivers/mtd/nand/pxa3xx_nand.c
+++ b/drivers/mtd/nand/pxa3xx_nand.c
@@ -1311,17 +1311,7 @@
 	.resume		= pxa3xx_nand_resume,
 };
 
-static int __init pxa3xx_nand_init(void)
-{
-	return platform_driver_register(&pxa3xx_nand_driver);
-}
-module_init(pxa3xx_nand_init);
-
-static void __exit pxa3xx_nand_exit(void)
-{
-	platform_driver_unregister(&pxa3xx_nand_driver);
-}
-module_exit(pxa3xx_nand_exit);
+module_platform_driver(pxa3xx_nand_driver);
 
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("PXA3xx NAND controller driver");