[media] mceusb: get misc port data from hardware

According to the specs, you can read the number of tx ports, number of
rx sensors, which tx ports have cables plugged into them, and which rx
sensors are active. In practice, most of my devices do seem to report
sane values for tx ports and rx sensors (but not all -- one without any
tx ports reports having them), and most report the active sensor
correctly, but only one of eight reports cabled tx ports correctly. So
for the most part, this is just for informational purposes.

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