spi: lpspi: Add the missing NULL check

The spi_transfer *t will be used in one transfer whatever. If t is NULL,
there has no need to try sending data, so add an error return here.
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Acked-by: Fugang Duan <Fugang.duan@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-lpspi.c

@@ -438,9 +438,12 @@ static int fsl_lpspi_setup_transfer(struct spi_controller *controller,
 	struct fsl_lpspi_data *fsl_lpspi =
 				spi_controller_get_devdata(spi->controller);
 
+	if (t == NULL)
+		return -EINVAL;
+
 	fsl_lpspi->config.mode = spi->mode;
-	fsl_lpspi->config.bpw = t ? t->bits_per_word : spi->bits_per_word;
-	fsl_lpspi->config.speed_hz = t ? t->speed_hz : spi->max_speed_hz;
+	fsl_lpspi->config.bpw = t->bits_per_word;
+	fsl_lpspi->config.speed_hz = t->speed_hz;
 	fsl_lpspi->config.chip_select = spi->chip_select;
 
 	if (!fsl_lpspi->config.speed_hz)