mm: ashmem: Add cache clean and invalidate ioctls for ashmem

Change-Id: I9475feb06c961cb8b27b434eaf3b54d2666331d4
Orig-Change-Id: Idc120f9f869c1a68e5f012327aa7f599ac065fce
CRs-fixed: 291124
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>