be2net: fix wrong frag_idx reported by RX CQ

The RX CQ can report completions with invalid frag_idx when the RXQ that
was *previously* using it, was not cleaned up properly. This hits
a BUG_ON() in be2net.

When completion coalescing is enabled on a CQ, an explicit CQ-notify
(with rearm) is needed for each compl, to flush partially coalesced CQ
entries that are pending DMA.

In be_close(), this fix now notifies CQ for each compl, waits explicitly
for the flush compl to arrive and complains if it doesn't arrive.

Also renaming be_crit_error() to be_hw_error() as it's the more
appropriate name and to convey that we don't wait for the flush compl
only when a HW error has occurred.

Signed-off-by: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>