Revert "msm: ion: Update the ion cache maintainance operations"

This reverts commit 1703713c

This commit led to boot failures for 32-bit 8939 builds and is being
reverted to allow progress while a more permanent solution is under
investigation.

Change-Id: Ia7a95cb019ba9b34b842ef8ed99f4f2b33cbe867
Signed-off-by: Ian Maund <imaund@codeaurora.org>