spi: fsl-lpspi: quit reading rx fifo under error condition

In case that error occurs during waiting for txfifo empty, it is
not necessary to read rx fifo. It's better to return directly.
Signed-off-by: Gao Pan <pandy.gao@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-fsl-lpspi.c

@@ -350,9 +350,12 @@ static int fsl_lpspi_transfer_one(struct spi_master *master,
 	}
 
 	ret = fsl_lpspi_txfifo_empty(fsl_lpspi);
+	if (ret)
+		return ret;
+
 	fsl_lpspi_read_rx_fifo(fsl_lpspi);
 
-	return ret;
+	return 0;
 }
 
 static int fsl_lpspi_transfer_one_msg(struct spi_master *master,