mlx4: fix QP tree trashing

When adding new unicast steer entry, before moving qp to state ready,
actually before calling mlx4_RST2INIT_QP_wrapper(), there were added
a lot of entries with local_qpn=0 into radix tree.
This fact impacted the get_res() function and proper functioning
of resource tracker in addition to adding trash entries into radix tree.

Signed-off-by: Eugenia Emantayev <eugenia@mellanox.co.il>
Reviewed-by: Yevgeny Petrilin <yevgenyp@melllanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>