Version: Update for TF-M v1.2.0 release

This patch updates the TF-M version for runtime code,
build system and documentation to v1.2.0

Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
Change-Id: I53b1e916a9928bac7347381d1a37c7d62bd2302a
5 files changed