drm/amdgpu/si: add dpm quirk for Oland

commit 18a8de1bc37e97dff1c96ee6cf49adbd02a0f775 upstream.

OLAND 0x1002:0x6604 0x1028:0x066F 0x00 seems to have problems
with higher sclks.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>