[media] s5p-tv: Fix potential NULL pointer dereference error

When mdev is NULL, the error print statement will try to dereference
the NULL pointer.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/s5p-tv/mixer_drv.c

diff --git a/drivers/media/platform/s5p-tv/mixer_drv.c b/drivers/media/platform/s5p-tv/mixer_drv.c
index a15ca05..ca0f297 100644
--- a/drivers/media/platform/s5p-tv/mixer_drv.c
+++ b/drivers/media/platform/s5p-tv/mixer_drv.c
@@ -384,7 +384,7 @@
 
 	mdev = kzalloc(sizeof *mdev, GFP_KERNEL);
 	if (!mdev) {
-		mxr_err(mdev, "not enough memory.\n");
+		dev_err(dev, "not enough memory.\n");
 		ret = -ENOMEM;
 		goto fail;
 	}