V4L/DVB (8628): bttv: Add support for Encore ENLTV2-FM

Thanks to Sistema Fenix (http://www.sistemafenix.com.br/

) and CDI Brasil
(www.cdibrasil.com.br/) for sponsoring this development.

Signed-off-by: Gilberto <gilberto@sistemafenix.com.br>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>