gpu: ion: Fixup merge conflicts and old code

During the course of merging patches, some of the merge conflict
fixups have resulted in minor differences from the upstream
tree. Additionally, some old code from removed features is
still present. Fixup those differences to avoid merge conflicts
and remove old code that isn't needed anymore.

Change-Id: I593162ca0b3482ad338173401a02cc03f94f9213
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>