This patch expands the RME documentation with description of TF-A
changes for RME. It also modifies some other parts of TF-A documentation
to account for RME changes.
Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: I9e6feeee235f0ba4b767d239f15840f1e0c540bb