chore(real_da): move realm DA support functions

Move realm DA support functions from realm_da.c
to realm_da_helpers.c.

Change-Id: I53f3d8bbcaa77d5d17a9b435c0e0484af64adbd7
Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
4 files changed