V4L/DVB: tm6000: avoid unknown symbol tm6000_debug

Reported by Stefan Ringel.

Thanks-to: Stefan Ringel <stefan.ringel@arcor.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/staging/tm6000/tm6000-video.c

@@ -56,6 +56,7 @@ static int video_nr = -1;		/* /dev/videoN, -1 for autodetect */
 
 /* Debug level */
 int tm6000_debug;
+EXPORT_SYMBOL_GPL(tm6000_debug);
 
 /* supported controls */
 static struct v4l2_queryctrl tm6000_qctrl[] = {