drm/amdgpu: cleanup some incorrect reg access for SRIOV

1)
we shouldn't load PSP kdb and sys/sos for VF, they are
supposed to be handled by hypervisor

2)
ih reroute doesn't work on VF thus we should avoid calling
it, besides VF should not use those PSP register sets for PF

3)
shouldn't load SMU ucode under SRIOV, otherwise PSP would report
error

Signed-off-by: Monk Liu <Monk.Liu@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>