drm/amdgpu: fix no interrupt issue for renoir emu

In renoir's ih model, there's a change in mmIH_CHICKEN
register, that limits IH to use physical address directly.
Those chicken bits need to be programmed first.

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