IB/mlx4: Fix port returned from query QP for QPs in INIT state

When a QP is in the INIT state, the sched_queue field hasn't been given 
to the firmware yet, so the firmware cannot return the value when the QP 
is queried.  To handle this, use the port number that is saved in the 
driver's QP data structure.

Found by Dotan Barak and Yaron Gepstein of Mellanox.

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>