drm/amdgpu: don't use legacy invalidation on MMHUB v3.3

Legacy invalidation is not supported.
This is missed during rebase.

Signed-off-by: Lang Yu <Lang.Yu@amd.com>
Reviewed-by: Yifan Zhang <yifan1.zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>