[media] lirc_zilog: Use kernel standard methods for marking device non-seekable

lirc_zilog had its own llseek stub that returned -ESPIPE.  Get rid of
it and use the kernel's no_llseek() and nonseekable_open() functions
instead.

Signed-off-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>