V4L/DVB: IR/mceusb: unify and simplify different gen device init

Started out as an effort to try to tackle the last remaining issue I'm
having with this damned pinnacle device getting wedged the first time
its plugged in after an indeterminate length of not being plugged in.
Didn't get that solved yet, but did streamline the init code a bit more
and remove some superfluous gunk. Nukes a completely unneeded call to
usb_device_init() and several lines of overly complex crap in the gen1
device init path.

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