drm/nouveau/kms/nv50-: Fix drm_dp_remove_payload() invocation

We changed the semantics for this in:

commit e761cc20 ("drm/display/dp_mst: Handle old/new payload states in
drm_dp_remove_payload()")

But I totally forgot to update this properly in nouveau. So, let's do that.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230613210529.552098-1-lyude@redhat.com