drm/amd/pm: conditionally disable pcie lane switching for some sienna_cichlid SKUs

Disable the pcie lane switching for some sienna_cichlid SKUs since it
might not work well on some platforms.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org