[media] ite-cir.c: get rid of warning: no previous prototype

drivers/media/rc/ite-cir.c:1711:5: warning: no previous prototype for 'ite_init' [-Wmissing-prototypes]
drivers/media/rc/ite-cir.c:1716:6: warning: no previous prototype for 'ite_exit' [-Wmissing-prototypes]

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