[media] xc4000: removed card_type

Removed the use of 'card_type' from the tuner configuration structure, and
replaced it with separate parameters to set board-specific configuration.

Signed-off-by: Istvan Varga <istvan_v@mailbox.hu>
Cc: Patrick Boettcher <pboettcher@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>