Improvements to link validation in media graph. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> From: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Link: https://patchwork.linuxtv.org/project/linux-media/patch/20240826141040.GC11033@pendragon.ideasonboard.com/