drm/amdgpu: remove special autoload handling for navi12

s/r list in rlc firmware is ready, so remove the special autoload handling

Signed-off-by: Xiaojie Yuan <xiaojie.yuan@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>