mtd: fsl-quadspi: Propagate the error from of_modalias_node()

The 'map_failed' label will return 'ret', so we need to assign the error
code to 'ret', otherwise the probe function will return success.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NHuang Shijie <shijie8@gmail.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

drivers/mtd/spi-nor/fsl-quadspi.c

@@ -905,7 +905,8 @@ static int fsl_qspi_probe(struct platform_device *pdev)
 		nor->prepare = fsl_qspi_prep;
 		nor->unprepare = fsl_qspi_unprep;
 
-		if (of_modalias_node(np, modalias, sizeof(modalias)) < 0)
+		ret = of_modalias_node(np, modalias, sizeof(modalias));
+		if (ret < 0)
 			goto map_failed;
 
 		ret = of_property_read_u32(np, "spi-max-frequency",