Old query_port code reports static MTU and link state values.
Instead, map actual MTU to next largest IB_MTU_* constant and
correctly report link state.

Cc: Steve Wise <swise@opengridcomputing.com>
Reported-by: NJeff Squyres <jsquyres@cisco.com>
Signed-off-by: NChien Tung <chien.tin.tung@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>