When freeing memory for the video buffers also remove them from the
irq & main queues.

This fixes an oops when doing the following:

open ("/dev/video", ..)
VIDIOC_REQBUFS
VIDIOC_QBUF
VIDIOC_REQBUFS
close ()

As the second VIDIOC_REQBUFS will cause the list entries of the buffers
to be cleared while they still hang around on the main and irc queues
Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: stable@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>