o lsi64854_enet_intr():

o lsi64854_enet_intr():
  - Like lsi64854_scsi_intr() return -1 in case there was a DMA error so
    the caller can distinguish it from a normal interrupt and leave the
    reset of the DMA engine to the caller so we don't kill any state there.
  - Move the static 'dodrain' flag to struct lsi64854_softc as there can
    be more than one LSI64854 used for a LANCE in a system and reset it
    again once draining the E-cache is done so we don't keep draining the
    cache with every interrupt.
  - Remove calling sc->sc_intrchain(), we will call lsi64854_enet_intr()
    via sc->intr() in the interrupt handler of the LANCE driver and not
    use it in chained mode.

o lsi64854_pp_intr():
  - Like lsi64854_scsi_intr() return -1 in case there was a DMA error so
    the caller can distinguish it from a normal interrupt.

o Remove the no longer used sc_intrchain* from struct lsi64854_softc.

o Make lsi64854_reset(), lsi64854_setup*() and lsi64854_*_intr() static
  to lsi64854.c as we do and will only call them via the respective
  function pointers in struct lsi64854_softc.

o While here fix style(9) bugs (variable definition inside a nested scope).