[media] smiapp: Use highest bits-per-pixel for sensor internal format

The format shown on the links internal to the sensor was the first one
enumerated from the sensor, not the highest bit depth data that can be
produced by the sensor. Correct this.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>