drm/amdgpu: Change IP init sequence to support PSP program IH_RB_CNTL on NV12 SRIOV

To enable PSP program IH_RB_CNTL,
the PSP IP should be initialized before IH IP, otherwise,
it will hit psp NULL pointer.

Signed-off-by: Peng Ju Zhou <PengJu.Zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>