drm/amdgpu: set fw default loading by psp for renoir

By default, set amdgpu ucode type to AMDGPU_FW_LOAD_PSP.

Acked-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Aaron Liu <aaron.liu@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>