msg/async/rdma: Make port number an attribute of the Connection not of the Device

msg/async/rdma: Make port number an attribute of the Connection not of the Device

Since multiple connections on different ports could exist, shouldn't use
device->active_port, instead use conn->ibport.
Or in other words, now Device object doesn't have an active_port,
instead every port specific action (create_qp, get_lid, get_gid etc.)
need to specify the port number. The information about the port number
is known to the connection (RDMAConnectedSocket*) who is the caller of
those actions.

Issue: 995322
Change-Id: I482cb87c04ba99845dc44f6dd0547835fe814ebf
Signed-off-by: Amir Vadai <amir@vadai.me>