linux-wandboard

[media] tuner-core: call has_signal for both TV and radio

If g_tuner is called and the tuner is able to return the signal strength
via has_signal(), call the tunner callback to retrieve such data for all
tuner types, not only for radio ones.

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