We had a script which was looping through the devices returned from
ibstat and attempted to register a SMI agent on an ethernet device.
This caused a kernel panic for IBoE devices that don't have QP0.

Fix this by checking if the QP exists before using it.
Signed-off-by: NIra Weiny <weiny2@llnl.gov>
Acked-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>