spi: stm32: do not mandate cs_gpio

CS gpios is not mandatory, the driver should allow working
even when CS are not given.
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://lore.kernel.org/r/1612551572-495-3-git-send-email-alain.volmat@foss.st.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-stm32.c

@@ -1944,12 +1944,6 @@ static int stm32_spi_probe(struct platform_device *pdev)
 		goto err_pm_disable;
 	}
 
-	if (!master->cs_gpiods) {
-		dev_err(&pdev->dev, "no CS gpios available\n");
-		ret = -EINVAL;
-		goto err_pm_disable;
-	}
-
 	dev_info(&pdev->dev, "driver initialized\n");
 
 	return 0;