- Increase RX coalesced packets from 32 to 129 to avoid being livelocked when

- Increase RX coalesced packets from 32 to 129 to avoid being livelocked when
  ~1.48Mpps 64bytes packets are injected.
- Increase RX coalescing ticks from 20 to 25 and correct the comment about its
  unit: it is 4us instead of 10us (thanks go to jsg@openbsd.org for giving me
  the informational material :).

# An interrupt is generated if
# (RX pkt count > ET_RX_INTR_NPKTS) || (timer > ET_RX_INTR_DELAY)
#
# I thought the interrupt generation condition was
# (RX pkt count > ET_RX_INTR_NPKTS) && (timer > ET_RX_INTR_DELAY)