Build: Add conditional build for secure context management

Secure context management is only needed in multiple secure context
model. This patch adds a build flag to disable context management.
It's set to ON by default.
Note that the NS client ID functionality will lose if secure context
management is disabled.

Change-Id: I06ed4fdee20a0192c54e2d08d453ee965ee3cbfc
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
2 files changed