[media] media: lirc_zilog: use a dynamically allocated lirc_dev

lirc_zilog currently embeds a struct lirc_dev in its own struct IR,
but subsequent patches will make the lifetime of struct lirc_dev
dynamic (i.e.  it will be free():d once lirc_dev is sure there are
no users of the struct).

Therefore, change lirc_zilog to use a pointer to a dynamically
allocated struct lirc_dev.

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>