The cache maintenance routines in ashmem were causing
several security issues. Since they are not being used
anymore by any drivers, its well to remove them entirely.

Bug: 34126808
Bug: 34173755
Bug: 34203176
CRs-Fixed: 1107034, 2001129, 2007786
Change-Id: I955e33d90b888d58db5cf6bb490905283374425b
Signed-off-by: Sudarshan Rajagopalan <sudaraja@codeaurora.org>
Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>