media: v4l2-pci-skeleton.c: fix outdated irq code

Fix the outdated irq example code. It is under an #ifdef TODO
so it is never actually compiled and this code was never compiled.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>