mmc: sdhci-s3c: constify uses of driver/match data

The driver data (struct sdhci_s3c_drv_data) stored in of_device_id
table is allocated as const and used only in const-way.  Skip
unnecessary const-away casts and convert all users to work with pointer
to const.  This is both more logical and safer.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Sylwester Nawrocki <snawrocki@kernel.org>
Link: https://lore.kernel.org/r/20210415084412.51125-3-krzysztof.kozlowski@canonical.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-s3c.c

@@ -462,21 +462,21 @@ static int sdhci_s3c_parse_dt(struct device *dev,
 }
 #endif
 
-static inline struct sdhci_s3c_drv_data *sdhci_s3c_get_driver_data(
+static inline const struct sdhci_s3c_drv_data *sdhci_s3c_get_driver_data(
 			struct platform_device *pdev)
 {
 #ifdef CONFIG_OF
 	if (pdev->dev.of_node)
-		return (struct sdhci_s3c_drv_data *)of_device_get_match_data(&pdev->dev);
+		return of_device_get_match_data(&pdev->dev);
 #endif
-	return (struct sdhci_s3c_drv_data *)
+	return (const struct sdhci_s3c_drv_data *)
 			platform_get_device_id(pdev)->driver_data;
 }
 
 static int sdhci_s3c_probe(struct platform_device *pdev)
 {
 	struct s3c_sdhci_platdata *pdata;
-	struct sdhci_s3c_drv_data *drv_data;
+	const struct sdhci_s3c_drv_data *drv_data;
 	struct device *dev = &pdev->dev;
 	struct sdhci_host *host;
 	struct sdhci_s3c *sc;
@@ -761,7 +761,7 @@ static const struct platform_device_id sdhci_s3c_driver_ids[] = {
 MODULE_DEVICE_TABLE(platform, sdhci_s3c_driver_ids);
 
 #ifdef CONFIG_OF
-static struct sdhci_s3c_drv_data exynos4_sdhci_drv_data = {
+static const struct sdhci_s3c_drv_data exynos4_sdhci_drv_data = {
 	.no_divider = true,
 };