V4L/DVB (9034): With the recent patch to v4l2 titled "v4l2: use register_chrdev_region

instead of register_chrdev", the internal reference count is no longer
necessary in order to free the internal stk_webcam struct. This patch
removes the reference counter from the stk_webcam struct and frees the
struct via the video_device release callback. It also fixes an
associated bug in stk_camera_probe which could result from
video_unregister_device being called before video_register_device.
Lastly, it simplifies access to the stk_webcam struct in several
places. This patch should apply cleanly against the "working" branch
of the v4l-dvb git repository.

This patch is identical to the patch I sent a couple of months back
titled "stk-webcam: Fix video_device handling" except that it has been
rebased against current modifications to stk-webcam and it no longer
depends on any other outstanding patches.

Acked-by: Jaime Velasco Juan <jsagarribay@gmail.com>
Signed-off-by: David Ellingsworth <david@identd.dyndns.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>