test(realm): add test for rtt_fold unassigned

Add testcase for RMI_RTT_FOLD,
for protected IPA unassigned empty and unassigned ram RTTs.
Host attempts to fold till max level permitted by Arch.
Fix helper to align with RMI call, remove unused code.

Change-Id: Ib94efa7ba60e028bb9f765e769fe377c101a71fc
Signed-off-by: Shruti Gupta <shruti.gupta@arm.com>
5 files changed