refactor(fvp_r): remove unused files and clean up makefiles

This patch removes files that are not used by TF-R as well as
removes unused generic files from the TF-R makefile.

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: Idb15ac295dc77fd38735bf2844efdb73e6f7c89b
14 files changed