drivers/rtc/rtc-max8998.c: check for pdata presence before dereferencing

Currently the driver can crash with a NULL pointer dereference if no
pdata is provided, despite of successful registration of the MFD part.
This patch fixes the problem by adding a NULL check before dereferencing
the pdata pointer.
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-max8998.c

@@ -285,7 +285,7 @@ static int max8998_rtc_probe(struct platform_device *pdev)
 			info->irq, ret);
 
 	dev_info(&pdev->dev, "RTC CHIP NAME: %s\n", pdev->id_entry->name);
-	if (pdata->rtc_delay) {
+	if (pdata && pdata->rtc_delay) {
 		info->lp3974_bug_workaround = true;
 		dev_warn(&pdev->dev, "LP3974 with RTC REGERR option."
 				" RTC updates will be extremely slow.\n");