media: s5p-mfc: Add checking to s5p_mfc_probe().

If of_device_get_match_data() return NULL,
then null pointer dereference occurs in s5p_mfc_init_pm().
The patch adds checking if dev->variant is NULL.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Nadezda Lutovinova <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/platform/s5p-mfc/s5p_mfc.c

···
 	}
 
 	dev->variant = of_device_get_match_data(&pdev->dev);
+	if (!dev->variant) {
+		dev_err(&pdev->dev, "Failed to get device MFC hardware variant information\n");
+		return -ENOENT;
+	}
 
 	dev->regs_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(dev->regs_base))