[media] pt3: make pt3_pm_ops() static

drivers/media/pci/pt3/pt3.c:862:1: warning: symbol 'pt3_pm_ops' was not declared. Should it be static?

Cc: Akihiro Tsukada <tskd08@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>