ion: Revert upstream changes for now

Upstream has made changes to the ion framework which are not compatible
with qcom-added features. Revert these temporarily until a proper
integration can be done.

Revert to:
commit d0164adc ("mm, page_alloc: distinguish between being unable to
sleep, unwilling to sleep and avoiding waking kswapd")

Also disable ION so that a snapshot can be properly applied on
top of it.

Change-Id: I81747f93dd3e4c408aa01a060b7d9b115158be2b
Signed-off-by: Liam Mark <lmark@codeaurora.org>