gpu: ion: Add callbacks to enable SMI voting in ION.

This change is part of the move from PMEM to ION. ION needs an SMI
voting interface smiliar to PMEM's.

Change-Id: I18888f46198848694fb7e1e0d2671074bf51d7c9
Signed-off-by: Alex Bird <alexbird@codeaurora.org>
3 files changed