drm/nouveau/disp: PIOR DP uses GPIO for HPD, not PMGR AUX interrupts

Fixes crash on boards with ANX9805 TMDS/DP encoders.

Cc: stable@vger.kernel.org # 6.4+
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230719044051.6975-2-skeggsb@gmail.com