cnic: Fix race conditions with firmware

During iSCSI connection terminations, if the target is also terminating
at about the same time, the firmware may not complete the driver's
request to close or reset the connection.  This is fixed by handling
other events (instead of the expected completion event) as an indication
that the driver's request has been rejected.

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