feat(rmmd): add FEAT_MEC support

This patch provides architectural support for further use of
Memory Encryption Contexts (MEC) by declaring the necessary
registers, bits, masks, helpers and values and modifying the
necessary registers to enable FEAT_MEC.

Signed-off-by: Tushar Khandelwal <tushar.khandelwal@arm.com>
Signed-off-by: Juan Pablo Conde <juanpablo.conde@arm.com>
Change-Id: I670dbfcef46e131dcbf3a0b927467ebf6f438fa4
8 files changed