spi: qup: Make of_device_id array const

Make of_device_id array const, because all OF functions
handle it as const.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-qup.c

@@ -749,7 +749,7 @@ static int spi_qup_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct of_device_id spi_qup_dt_match[] = {
+static const struct of_device_id spi_qup_dt_match[] = {
 	{ .compatible = "qcom,spi-qup-v2.1.1", },
 	{ .compatible = "qcom,spi-qup-v2.2.1", },
 	{ }