drm/amdgpu/discovery: set family for GC 11.0.2

Set AMDGPU_FAMILY_GC_11_0_0.

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Flora Cui <flora.cui@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>