drm/amd/display: disable power gating for DCN314

[Why]
Power gating is causing error messages on some DCN314 systems

[How]
Force disable power gating for DCN314

Fixes: 4cc1cebe ("drm/amd/display: Re-enable DPP/HUBP Power Gating")
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Daniel Miess <daniel.miess@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>