myri10ge: Use the pause counter to avoid a needless device reset

Use the pause counter to avoid a needless device reset, and
print a message telling the admin that our link partner is
flow controlling us down to 0 pkts/sec.

Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>