drm/amdgpu: Add amdgpu_sriov_multi_vf_mode function

Use amdgpu_sriov_multi_vf_mode to replace amdgpu_sriov_vf(adev) && !amdgpu_sriov_is_pp_one_vf(adev).

Signed-off-by: Emily Deng <Emily.Deng@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>