linux-phytec-fsl

drm/nouveau/disp/dp: maintain link in response to hpd signal

This previously worked for the most part due to userspace doing a
modeset in response to HPD interrupts.  This will allow us to
properly handle cases where sync is lost for other reasons, or if
userspace isn't caring.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>