[media] mxl5005s: fix: don't discard bandwidth changes

There is a bug on mxl5005s logic: when the bandwidth changes, but using
the same delivery system, the code discard the set_params()
reconfiguration request.

This was happening because, in the previous coding, the bandwidth
calculus were after the check for delivery system changes.

The previous patch changed the logic to estimate the bandwidth to
happend together with the changes at the delivery system.

So, with a one-statement change, it is possible to make the tuner to
reconfigure, in order to adjust to bandwidth changes. this will
likely fix issues on countries that use 7MHz/8MHz DVB-T channels.

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