V4L/DVB (9775): tda8290: fix FM radio

tda8290 were using some random video standard for FM. This results on random
errors. Instead, program tda8290 in expert mode, using a configuration near the
one specified on NXP datasheet for tda8295 (available on their site).

Also, properly display that the device is on radio mode.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>