wireless: libertas: use dev_get_platdata()

Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly. This is a cosmetic change
to make the code simpler and enhance the readability.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/libertas/if_spi.c b/drivers/net/wireless/libertas/if_spi.c
index 4bb6574..5d39ec8 100644
--- a/drivers/net/wireless/libertas/if_spi.c
+++ b/drivers/net/wireless/libertas/if_spi.c
@@ -1128,7 +1128,7 @@
 {
 	struct if_spi_card *card;
 	struct lbs_private *priv = NULL;
-	struct libertas_spi_platform_data *pdata = spi->dev.platform_data;
+	struct libertas_spi_platform_data *pdata = dev_get_platdata(&spi->dev);
 	int err = 0;
 
 	lbs_deb_enter(LBS_DEB_SPI);