bnx2x: dcb - send all unmapped priorities to same COS as L2

bnx2x: dcb - send all unmapped priorities to same COS as L2

As a result of DCBX negotiation some priorities maybe untouched and still
unmapped to any COS; instead of sending them to COS0 we assign them
to the same COS as L2 traffic - to avoid collisions with storage class of
service.

Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 09b775e7ec08ae92b8d976b7e34ba7f83b904c97)

Signed-off-by: Joe Jin <joe.jin@oracle.com>