drm/todo: Add entry to remove load/unload hooks

They're midlayer, broken, and because of the old gunk, we can't fix
them. For examples see the various checks in drm_mode_object.c against
dev->registered, which cannot be enforced if the driver still uses the
load hook.

Unfortunately our biggest driver still uses load/unload, so this would
be really great to get fixed.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191023144953.28190-2-daniel.vetter@ffwll.ch