V4L/DVB (5132): M920x: more trivial cleanups

- Removed some needless brances
- Removed an unneeded check for adapter[0]
- Removed unneeded declaration of .generic_bulk_ctrl_endpoint = 0x01

Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>