feat(rme): add context management changes for FEAT_RME

This patch adds a new context for realm world and realm world
awareness in context management.

Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Signed-off-by: Subhasish Ghosh <subhasish.ghosh@arm.com>
Change-Id: Ic17469393603e789d7adc025880346bc3d6233d7
4 files changed