[media] CXD2820r: Query DVB frontend delivery capabilities

Override default delivery system information provided by FE_GET_INFO,
so that applications can enumerate delivery systems provided by the
frontend.

Signed-off-by: Manu Abraham <abraham.manu@gmail.com>
Acked-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>