[media] radio-miropcm20: fix querycap

Don't set version (done by the v4l2 core), fill in bus_info, set correct
driver name and add device_caps support.

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