[MTD] Cleanup of 'ioremap balanced with iounmap for drivers/mtd subsystem'

Updated version of patch, in response to comments from Francois Romieu
<romieu@fr.zoreil.com>

Remove gratuitous casts from iounmap and initialisation of variables.

Signed-off-by: Amol Lad <amol@verismonetworks.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/drivers/mtd/nand/edb7312.c b/drivers/mtd/nand/edb7312.c
index 12017f3..1daf823 100644
--- a/drivers/mtd/nand/edb7312.c
+++ b/drivers/mtd/nand/edb7312.c
@@ -199,7 +199,7 @@
 	nand_release(ap7312_mtd);
 
 	/* Release io resource */
-	iounmap((void *)this->IO_ADDR_R);
+	iounmap(this->IO_ADDR_R);
 
 	/* Free the MTD device structure */
 	kfree(ep7312_mtd);