Register NS shared memory for SP's activity logs and TA sessions

Register NS shared memory for SP's activity logs and TA sessions

This patch registers NS memory buffer with the secure payload using
two different functions IDs - REGISTER_LOGBUF, REGISTER_REQBUF.

a. The SP uses the log-buffer to store its activity logs, in a
pre-decided format. This helps in debugging secure payload's issues.
b. The SP uses the req-buffer to get the parameters required by
sessions with Trusted Applications.

Change-Id: I6b0247cf7790524132ee0da24f1f35b1fccec5d5
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>