drm/nouveau/disp: rename internal output acquire/release functions

These will be made static later in the patch series, after the code that
uses them has been cleaned up in preparation for GSP-RM support.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Danilo Krummrich <me@dakr.org>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919220442.202488-10-lyude@redhat.com