sequentializeDMA read and write requests in bluesim they way they are in PCIe

Change-Id: Iab28a8292e1c4c67c49586cbc3d0cdb449c47bfb
added mkConnection for DMA clients and servers

Change-Id: Ib8d79a8d2de723f90ebd20496c71e8d1476a5fdb