V4L/DVB (13617): ir: move input_register_device() to happen inside ir_input_register()

We'll need to register a sysfs class for the IR devices. As such, the better
is to have the input_register_device()/input_unregister_device() inside
the ir register/unregister functions.

Also, solves a naming problem with V4L ir_input_init() function, that were,
in fact, registering a device.

While here, do a few cleanups at budget-ci IR logic.

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