[media] lirc.h: remove several unused ioctls

While reviewing the documentation gaps on LIRC, it was
noticed that several ioctls aren't used by any LIRC drivers
(nor at staging or mainstream).

It doesn't make sense to document them, as they're not used
anywhere. So, let's remove those from the lirc header.

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