echo via ring buffer

Change-Id: I5008411e957218625a8a0cdd8415f3ada9ea3c46
added support for S2H request portals via shared memory

Change-Id: Ie2d011a8cfb965533babb2ec4b29a2ffcd0c8fa0
removed unused dmaErrorFifo

Change-Id: I795ef76189de2c6fd740c825afafa781dddde657
moved "error" method from DmaDebugIndication to MMUConfigIndication

Change-Id: I9465ca3d4b22132f599e10660a58a37864e79342