drm/amd/display: Disable OTG WA for the plane_state NULL case on DCN314

[Why]
This shouldn't trigger during tiled display hotplug/unplug but it does
because one of the tiles can end up with a NULL plane state.

This also doesn't guard against the hang that it was originally trying
to resolve, and can instead cause DIO corruption due to OTG sync
being lost.

[How]
This was reverted at one point out of DCN31 so revert it here too.

Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>