fintek-cir: get rid of warning: no previous prototype

Cc: Linux Media Mailing List <linux-media@vger.kernel.org>

drivers/media/rc/fintek-cir.c:687:5: warning: no previous prototype for 'fintek_init' [-Wmissing-prototypes]
drivers/media/rc/fintek-cir.c:692:6: warning: no previous prototype for 'fintek_exit' [-Wmissing-prototypes]

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