drm_hwcomposer: Fix HiSi import fail log spam

drm_hwcomposer: Fix HiSi import fail log spam

hikey can only display layers which do not have gralloc usage HW_FB
(hint: that leaves just the client target layer). As such, there's no
benefit trying to import them since it'll just fail. So if we encounter
a layer such as this, fake the import (the release will be a noop since
gem_handles will be 0).

Also, as a belt-and-suspenders move, replace the greedy planner with one
that only displays (usage != HW_FB) to be doubly sure that we don't try
to display the no-op layers

Change-Id: I7bf88cfb7bda1dd5f47b741709619494431558a2
Signed-off-by: Sean Paul <seanpaul@chromium.org>