[media] lirc_zilog: Always allocate a Rx lirc_buffer object

Always allocate a lirc_buffer object, instead of just upon setup of
the Rx i2c_client.  If we do not allocate a lirc_buffer object, because
we are not handling the Rx i2c_client, lirc_dev will allocate its own
lirc_buffer anyway and not tell us about its location.

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>