mlx4_ib: Fix SIDR support of for UD QPs under SRIOV/RoCE

* Handle CM_SIDR_REQ_ATTR_ID and CM_SIDR_REP_ATTR_ID
  in multiplex_cm_handler and demux_cm_handler.

* Handle Service ID Resolution messages and REQ messages
  separately, for their formats are different.

Signed-off-by: Shani Michaeli <shanim@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>