drm/amd/amdgpu: configure beige_goby gfx according to gfx 10.3's definition

The gfx version of beige_goby is 10.3,
identical to sienna_cichlid,
follow the way of sienna_cichlid

Signed-off-by: Chengming Gui <Jack.Gui@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>