msm: adsprpc: Handle UAF in process shell memory

Added flag to indicate memory used
in process initialization. And, this memory
would not removed in internal unmap to avoid
UAF or double free.

Issue: FP3SEC-168
Change-Id: Ifa621dee171b3d1f98b82302c847f4d767f3e736
Signed-off-by: Swathi K <kataka@codeaurora.org>
(cherry picked from commit 59d96fe1)