cnic: Reset iSCSI EQ during shutdown.

Without the reset, reloading the cnic driver can cause the iSCSI
Event Queue to be out of sync with the driver and cause intermittent
crash.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Acked-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>