feat(rmm-eac4): update RSI_VERSION, add RSI_FEATURES

This patch updates API of RSI_VERSION and adds new
RSI_FEATURES command handler as per RMM Specification
1.0-eac4.
RSI_ABI_VERSION_MAJOR is updated from 13 to 14.

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: I7d445d18ee7fddf9f20c51f2a45fd334cb17b454
9 files changed