[media] Guard a divide in v4l1 compat layer

Hi,
  I managed to trigger a divide by 0 in the v4l compat code
with the mem2mem test module; I suspect perhaps it shouldn't
have been returning a 0 pixel wide picture, but either way it seems
right to guard this divide by 0 in the compatibility layer.

Tested on 2.6.36 (ubuntu build, but the code in this is the same as upstream),
but ***not tested with a real video device***.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
cc: stable.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l1-compat.c

@@ -645,9 +645,16 @@ static noinline long v4l1_compat_get_picture(
 		goto done;
 	}
 
-	pict->depth   = ((fmt->fmt.pix.bytesperline << 3)
-			 + (fmt->fmt.pix.width - 1))
-			 / fmt->fmt.pix.width;
+	if (fmt->fmt.pix.width)
+	{
+		pict->depth   = ((fmt->fmt.pix.bytesperline << 3)
+				 + (fmt->fmt.pix.width - 1))
+				 / fmt->fmt.pix.width;
+	} else {
+		err = -EINVAL;
+		goto done;
+	}
+
 	pict->palette = pixelformat_to_palette(
 		fmt->fmt.pix.pixelformat);
 done: