pxa168fb: fix incorrect resource calculation

The size calculation is not correct.  It should be end - start + 1.
Use resource_size() to caculate it.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

drivers/video/pxa168fb.c

@@ -668,7 +668,7 @@ static int __init pxa168fb_probe(struct platform_device *pdev)
 	/*
 	 * Map LCD controller registers.
 	 */
-	fbi->reg_base = ioremap_nocache(res->start, res->end - res->start);
+	fbi->reg_base = ioremap_nocache(res->start, resource_size(res));
 	if (fbi->reg_base == NULL) {
 		ret = -ENOMEM;
 		goto failed;