spi: constify of_device_id array

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mpc512x-psc.c

@@ -588,7 +588,7 @@ static int mpc512x_psc_spi_of_remove(struct platform_device *op)
 	return mpc512x_psc_spi_do_remove(&op->dev);
 }
 
-static struct of_device_id mpc512x_psc_spi_of_match[] = {
+static const struct of_device_id mpc512x_psc_spi_of_match[] = {
 	{ .compatible = "fsl,mpc5121-psc-spi", },
 	{},
 };

drivers/spi/spi-octeon.c

@@ -238,7 +238,7 @@ static int octeon_spi_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static struct of_device_id octeon_spi_match[] = {
+static const struct of_device_id octeon_spi_match[] = {
 	{ .compatible = "cavium,octeon-3010-spi", },
 	{},
 };

drivers/spi/spi-st-ssc4.c

@@ -482,7 +482,7 @@ static const struct dev_pm_ops spi_st_pm = {
 	SET_RUNTIME_PM_OPS(spi_st_runtime_suspend, spi_st_runtime_resume, NULL)
 };
 
-static struct of_device_id stm_spi_match[] = {
+static const struct of_device_id stm_spi_match[] = {
 	{ .compatible = "st,comms-ssc4-spi", },
 	{},
 };