Self-tests following boot from SAN have failed as the
UNDI driver might leave some NIG interrupt indications.

This patch does the clean-up, clearing those indications
and allowing the test to pass.
Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>