mg_disk: fix error return code in mg_probe()

Fix to return a negative error code from the error handling
case instead of 0, as returned elsewhere in this function.
Signed-off-by: NWei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/block/mg_disk.c

@@ -890,8 +890,10 @@ static int mg_probe(struct platform_device *plat_dev)
 	gpio_direction_output(host->rst, 1);
 
 	/* reset out pin */
-	if (!(prv_data->dev_attr & MG_DEV_MASK))
+	if (!(prv_data->dev_attr & MG_DEV_MASK)) {
+		err = -EINVAL;
 		goto probe_err_3a;
+	}
 
 	if (prv_data->dev_attr != MG_BOOT_DEV) {
 		rsc = platform_get_resource_byname(plat_dev, IORESOURCE_IO,