V4L/DVB (11392): patch: s2255drv driver removal problem fixed

This patch fixes kfree problem on driver removal, fixes streamoff problem
and removes unnecessary videobuf_waiton from free_buffer function.

Signed-off-by: Dean Anderson <dean@sensoray.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>