[media] cx25821: fix log_status, querycap

log_status shouldn't print LOG STATUS lines, the core does that already.
Fix querycap version number and add device_caps support.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>