Update the main branch and add the following changes:

 - update all SPs to support and use FF-A v1.1
 - update the project to support Armv8.5-A Branch Protection feature.
 - add a new FWU agent implementation, which implements a PSA Certified
   Firmware Update API 1.0 client. This allows implementing an FWU proxy
   on A+M systems.
 - add a new shared library called "libpsats" to help integrating the
   PSA clients to 3rd party linux user-space projects

For more details please refer to the change log.

Change-Id: I6baed8c340bfe47a019f870df0d543bb8e4da543
Signed-off-by: Gyorgy Szing <gyorgy.szing@arm.com>