spi: rockchip: Set GPIO_SS flag to enable Slave Select with GPIO CS

The rockchip spi still requires slave selection when using GPIO CS.
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-rockchip.c

@@ -749,6 +749,7 @@ static int rockchip_spi_probe(struct platform_device *pdev)
 	master->transfer_one = rockchip_spi_transfer_one;
 	master->max_transfer_size = rockchip_spi_max_transfer_size;
 	master->handle_err = rockchip_spi_handle_err;
+	master->flags = SPI_MASTER_GPIO_SS;
 
 	rs->dma_tx.ch = dma_request_chan(rs->dev, "tx");
 	if (IS_ERR(rs->dma_tx.ch)) {