Fixes to the bus, and added fields to the packet.

Fixes to the bus, and added fields to the packet.

src/mem/bus.cc:
    Put back the check to see if the bus is busy. Also, populate the fields in the packet to indicate when the first word and the entire packet will be delivered.
src/mem/bus.hh:
    Remove the occupyBus function.
src/mem/packet.hh:
    Added fields to the packet to indicate when the first chunk of a packet arrives, and when the entire packet arrives.

--HG--
extra : convert_revision : cfc7670a33913d48a04d02c6d2448290a51f2d3c