mtd: simplify return logic in do_map_probe()

Signed-off-by: Uwe Kleine-König <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

drivers/mtd/chips/chipreg.c

···
 	*/
 	module_put(drv->module);
 
-	if (ret)
-		return ret;
-
-	return NULL;
+	return ret;
 }
 /*
  * Destroy an MTD device which was created for a map device.