drm/nouveau/dp: Don't probe eDP ports twice harder

I didn't pay close enough attention the last time I tried to fix this
problem - while we currently do correctly take care to make sure we don't
probe a connected eDP port more then once, we don't do the same thing for
eDP ports we found to be disconnected.

So, fix this and make sure we only ever probe eDP ports once and then leave
them at that connector state forever (since without HPD, it's not going to
change on its own anyway). This should get rid of the last few GSP errors
getting spit out during runtime suspend and resume on some machines, as we
tried to reprobe eDP ports in response to ACPI hotplug probe events.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240404233736.7946-3-lyude@redhat.com