drm/amdgpu: correct gpu clock counter query on cyan skilfish

Cayn skilfish uses SMUIO v11.0.8 offset.

Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Reviewed-by: Aaron Liu <aaron.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: <stable@vger.kernel.org> # v5.15+