[media] omap3isp: ccdc: Fix crash in HS/VS interrupt handler

The HS/VS interrupt handler needs to access the pipeline object. It
erronously tries to get it from the CCDC output video node, which isn't
necessarily included in the pipeline. This leads to a NULL pointer
dereference.

Fix the bug by getting the pipeline object from the CCDC subdev entity.

Reported-by: Gary Thomas <gary@mlbassoc.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>