IP based RoCE gids don't store Ethernet L2 parameters, MAC and VLAN.

Therefore, we need to extract them from the CQE and place them in
struct ib_wc (to be used for cases were they were taken from the gid).

Also, when modifying a QP or building address handle, instead of
parsing the dgid to get the MAC and VLAN, take them from the address
handle attributes.
Signed-off-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>