msm: smp2p: convert to secured smem feature

The shared memory (smem) driver provides a feature where point-to-point
smem items shared between Linux apps and one other remote processor are
protected against a number of attacks by security hardware, provided system
support exists.  Clients of the smem driver must elect to use this feature
if applicable.

SMP2P is a point-to-point communication protocol to which the security
feature applies.  Update SMP2P to make use of the security feature.

Change-Id: Ief920a2074d43507f727bfcb02ad1997f3f78c28
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>