[media] cxd2820r: switch automatically between DVB-T and DVB-T2

Remove old DVB-T2 freq module param and detect DVB-T/T2 automatically.

Implementation is trial and error, if DVB-T does not lock try DVB-T2
and vice versa. That's done by replacing normal DVBFE_ALGO_SW with
DVBFE_ALGO_CUSTOM which gives better control for tuning process.

DVB-C still uses normal software ZigZag, DVBFE_ALGO_SW.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>