ioremap balanced with iounmap for drivers/mtd subsystem

ioremap must be balanced by an iounmap and failing to do so can result
in a memory leak.

Tested (compilation only) with:
- allmodconfig
- Modifying drivers/mtd/maps/Kconfig and drivers/mtd/nand/Kconfig to
make sure that the changed file is compiling without warning

Signed-off-by: Amol Lad <amol@verismonetworks.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/drivers/mtd/nand/ppchameleonevb.c b/drivers/mtd/nand/ppchameleonevb.c
index 22fa65c..eb7d4d4 100644
--- a/drivers/mtd/nand/ppchameleonevb.c
+++ b/drivers/mtd/nand/ppchameleonevb.c
@@ -276,6 +276,7 @@
 	/* Scan to find existence of the device (it could not be mounted) */
 	if (nand_scan(ppchameleon_mtd, 1)) {
 		iounmap((void *)ppchameleon_fio_base);
+		ppchameleon_fio_base = NULL;
 		kfree(ppchameleon_mtd);
 		goto nand_evb_init;
 	}
@@ -314,6 +315,8 @@
 	ppchameleonevb_mtd = kmalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip), GFP_KERNEL);
 	if (!ppchameleonevb_mtd) {
 		printk("Unable to allocate PPChameleonEVB NAND MTD device structure.\n");
+		if (ppchameleon_fio_base)
+			iounmap(ppchameleon_fio_base);
 		return -ENOMEM;
 	}
 
@@ -322,6 +325,8 @@
 	if (!ppchameleonevb_fio_base) {
 		printk("ioremap PPChameleonEVB NAND flash failed\n");
 		kfree(ppchameleonevb_mtd);
+		if (ppchameleon_fio_base)
+			iounmap(ppchameleon_fio_base);
 		return -EIO;
 	}
 
@@ -378,6 +383,8 @@
 	if (nand_scan(ppchameleonevb_mtd, 1)) {
 		iounmap((void *)ppchameleonevb_fio_base);
 		kfree(ppchameleonevb_mtd);
+		if (ppchameleon_fio_base)
+			iounmap(ppchameleon_fio_base);
 		return -ENXIO;
 	}
 #ifdef CONFIG_MTD_PARTITIONS