memory: atmel-sdramc: fix a possible NULL dereference

of_match_device could return NULL, and so cause a NULL pointer
dereference later.

For fixing this problem, we use of_device_get_match_data(), this will
simplify the code a little by using a standard function for
getting the match data.

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/memory/atmel-sdramc.c

@@ -53,12 +53,10 @@ static const struct of_device_id atmel_ramc_of_match[] = {
 
 static int atmel_ramc_probe(struct platform_device *pdev)
 {
-	const struct of_device_id *match;
 	const struct at91_ramc_caps *caps;
 	struct clk *clk;
 
-	match = of_match_device(atmel_ramc_of_match, &pdev->dev);
-	caps = match->data;
+	caps = of_device_get_match_data(&pdev->dev);
 
 	if (caps->has_ddrck) {
 		clk = devm_clk_get(&pdev->dev, "ddrck");