feat(ff-a): update FF-A version to v1.2

Bump the required FF-A version in framework and manifests to v1.2 as
upstream feature development goes.

Signed-off-by: Kathleen Capella <kathleen.capella@arm.com>
Change-Id: I09d936d4aad89965cfd13f58741d647223b63a34
5 files changed