drm/nouveau: use connector events for HPD instead of GPIO watching

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

diff --cc drivers/gpu/drm/nouveau/nouveau_connector.c
Simple merge

diff --cc drivers/gpu/drm/nouveau/nouveau_connector.h
Simple merge

diff --cc drivers/gpu/drm/nouveau/nouveau_display.c
Simple merge