Add ARMv8.3 pointer authentication support

ARMv8.3-PAuth adds functionality that supports address authentication of
the contents of a register before that register is used as the target of
an indirect branch, or as a load.

This feature is supported only in AArch64 state.

This feature is mandatory in ARMv8.3 implementations.

This patch adds the functionality needed for platforms to provide
authentication keys for the TF-A Test Framework, and a new option
(ENABLE_PAUTH) to enable pointer authentication in the framework itself.
This option is disabled by default.

Pointer authentication support has been added to FVP.

Change-Id: Id2d5c978deb68ae60107879f1c3d0b231cba9f42
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/defaults.mk b/defaults.mk
index 0f74652..cf90aaf 100644
--- a/defaults.mk
+++ b/defaults.mk
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2018, Arm Limited. All rights reserved.
+# Copyright (c) 2018-2019, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -26,6 +26,9 @@
 # Build platform
 DEFAULT_PLAT		:= fvp
 
+# Enable Pointer Authentication support in the TFTF
+ENABLE_PAUTH		:= 0
+
 # Whether the Firmware Update images (i.e. NS_BL1U and NS_BL2U images) should be
 # built. The platform makefile is free to override this value.
 FIRMWARE_UPDATE		:= 0