IB/mlx4: Fix memory leak if QP creation failed

When RC, UC, or RAW QPs are created, a qp object is allocated (kzalloc).
If at a later point (in procedure create_qp_common) the qp creation fails,
this qp object must be freed.

Fixes: 1ffeb2eb ("IB/mlx4: SR-IOV IB context objects and proxy/tunnel SQP support")
Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>