IB/mlx4: Fix SL to 802.1Q priority-bits mapping for IBoE

For IBoE, SLs 0-7 are mapped to Ethernet 802.1Q user priority bits
(pbits) which are part of the VLAN tag, SLs 8-15 are reserved.

Under Ethernet, the ConnectX firmware treats (decode/encode) the four
bit SL field in various constructs such as QPC / UD WQE / CQE as PPP0
and not as 0PPP. This correlates well to the fact that within the
vlan tag the pbits are located in bits 15-13 and not 12-14.

The current code wasn't consistent around that area - the
encoding was correct for the IBoE QPC.path.schedule_queue field,
but was wrong for IBoE CQEs and when MLX header was built.

These inconsistencies resulted in wrong SL <--> wire 802.1Q pbits
mapping, which is fixed by using SL <--> PPP0 all around the place.

Signed-off-by: Oren Duer <oren@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/mlx4/ah.c

@@ -126,7 +126,7 @@ static struct ib_ah *create_iboe_ah(struct ib_pd *pd, struct ib_ah_attr *ah_attr
 		ah->av.ib.dlid = cpu_to_be16(0xc000);
 
 	memcpy(ah->av.eth.dgid, ah_attr->grh.dgid.raw, 16);
-	ah->av.eth.sl_tclass_flowlabel = cpu_to_be32(ah_attr->sl << 28);
+	ah->av.eth.sl_tclass_flowlabel = cpu_to_be32(ah_attr->sl << 29);
 
 	return &ah->ibah;
 }