Revert "drm/amdgpu: use HMM callback to replace mmu notifier"

This reverts commit 57731a07795ae80790c6ae7d8e7001cdbd6d14c0.

This depends on an HMM fix which is not upstream yet.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
4 files changed