[media] media: rename struct lirc_driver to struct lirc_dev

This is in preparation for the later patches which do away with
struct irctl entirely.

Signed-off-by: David Härdeman <david@hardeman.nu>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>