TFTF: Add ARMv8.5 BTI-related definitions

This patch adds BTI-related definitions in header files
which fully correspond to those in TF-A source tree.

Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
Change-Id: I1ae4c13dab41b0099517dd1bead221909511f2fc
3 files changed