mtd: nand: omap: free region as per resource size

memory as is now obtained via resource, upon freeing use
resource size. This also helps get rid of one macro.

Signed-off-by: Afzal Mohammed <afzal@ti.com>

drivers/mtd/nand/omap2.c

@@ -1513,7 +1513,7 @@ static int omap_nand_remove(struct platform_device *pdev)
 	/* Release NAND device, its internal structures and partitions */
 	nand_release(&info->mtd);
 	iounmap(info->nand.IO_ADDR_R);
-	release_mem_region(info->phys_base, NAND_IO_SIZE);
+	release_mem_region(info->phys_base, info->mem_size);
 	kfree(info);
 	return 0;
 }