reduce combinational path in mkMemSlave
reduce combinational path in mkMemSlave

Change-Id: I972146a84114ba03a05f482fa3c6f6cd68e56f21

cambridgehackers/connectal,cambridgehackers/connectal,cambridgehackers/connectal,8l/connectal,hanw/connectal,chenm001/connectal,chenm001/connectal,chenm001/connectal,cambridgehackers/connectal,chenm001/connectal,csail-csg/connectal,hanw/connectal,8l/connectal,8l/connectal,chenm001/connectal,csail-csg/connectal,csail-csg/connectal,csail-csg/connectal,csail-csg/connectal,8l/connectal,hanw/connectal,8l/connectal,hanw/connectal,cambridgehackers/connectal,hanw/connectal