mtd: orion_nand: Fix build failure caused by typo

Commit e9903060 ("mtd: orion_nand.c: add 
error handling and use resource_size()") introduced a build error -- it 
assigns something to a undeclared variable 'err', whereas the rest of 
the code uses 'ret' for this task.

This patch fixes this typo and thus removes the build failure.
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/mtd/nand/orion_nand.c

@@ -92,7 +92,7 @@ static int __init orion_nand_probe(struct platform_device *pdev)
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res) {
-		err = -ENODEV;
+		ret = -ENODEV;
 		goto no_res;
 	}