Minor further cleanup & commenting of Packet class.

Minor further cleanup & commenting of Packet class.

src/cpu/simple/atomic.cc:
    Make common ifetch setup based on Request rather than Packet.
    Packet::reset() no longer a separate function.
    sendAtomic() returns latency, not absolute tick.
src/cpu/simple/atomic.hh:
    sendAtomic returns latency, not absolute tick.
src/cpu/simple/base.cc:
src/cpu/simple/base.hh:
src/cpu/simple/timing.cc:
    Make common ifetch setup based on Request rather than Packet.
src/dev/alpha_console.cc:
src/dev/ide_ctrl.cc:
src/dev/io_device.cc:
src/dev/isa_fake.cc:
src/dev/ns_gige.cc:
src/dev/pciconfigall.cc:
src/dev/sinic.cc:
src/dev/tsunami_cchip.cc:
src/dev/tsunami_io.cc:
src/dev/tsunami_pchip.cc:
src/dev/uart8250.cc:
src/mem/physical.cc:
    Get rid of redundant Packet time field.
src/mem/packet.cc:
    Eliminate reset() method.
src/mem/packet.hh:
    Fold reset() function into reinitFromRequest()... it was
    only ever called together with that function.
    Get rid of redundant time field.
    Cleanup/add comments.
src/mem/port.hh:
    Document in comment that sendAtomic returns latency, not absolute tick.

--HG--
extra : convert_revision : 0252f1a294043ca3ed58f437232ad24fc0733e0c