drm/amdgpu: add gfx ip block for sienna_cichlid (v3)

Add support for GC 10.3.

v2: Squash in gb_addr_config fix (Alex)
v3: Add num_pkrs support (Alex)

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