drm/amdgpu: Set GC family for GC 11.0.3

Set AMDGPU_FAMILY_GC_11_0_0.

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