drm/amdgpu: disable 3D pipe 1 on Navi1x

[why]
CP firmware decide to skip setting the state for 3D pipe 1 for Navi1x as there
is no use case.

[how]
Disable 3D pipe 1 on Navi1x.

Reviewed-by: Feifei Xu <Feifei.Xu@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Tianci.Yin <tianci.yin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>