lib: sm: FF-A messages now carry Trusty SM calls If FFA_MSG_WAIT is supported, then Trusty API calls are encapsulated within FF-A direct messages. Bug: 284057071 Signed-off-by: Ben Horgan <ben.horgan@arm.com> Change-Id: I7abee0c070f4d45ed7518691c0f0c332ce5e813f