spi: use dev_get_platdata()

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c
index 29fce6a..de0976c 100644
--- a/drivers/spi/spi-mpc512x-psc.c
+++ b/drivers/spi/spi-mpc512x-psc.c
@@ -474,7 +474,7 @@
 					      u32 size, unsigned int irq,
 					      s16 bus_num)
 {
-	struct fsl_spi_platform_data *pdata = dev->platform_data;
+	struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
 	struct mpc512x_psc_spi *mps;
 	struct spi_master *master;
 	int ret;