drm/amd/amdgpu: set disabled vcn to no_schduler

[Why]
after the reset domain introduced, the sched.ready will be init after
hw_init, which will overwrite the setup in vcn hw_init, and lead to
vcn ib test fail.

[How]
set disabled vcn to no_scheduler

Fixes: 5fd8518d ("drm/amdgpu: Move scheduler init to after XGMI is ready")
Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
Acked-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>