qlge: Fix occasional loopback test failure.

On some servers we see the cleaning of the RX queue finish before all
the loopback packets are sent out.  This delay allows the queues to
settle before checking for successful completion.
Also, delay completion so link has time to come back up.

Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>