feat(realm): update rsi_ipa_state_get() function

This patch updates rsi_ipa_state_get() function and its
related test calls as per RMM Specification 1.0-rel0-rc1.
It also updates RSI commands API related comments and
makes minor changes in test functions to improve code
readability.

Change-Id: I28f69967ab6ff5b38c2b9efd423b0e8b4ad61dae
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
3 files changed