IB/core: Destroy QP if XRC QP fails

The open-coded variant missed destroy of SELinux created QP, reuse already
existing ib_detroy_qp() call and use this opportunity to clean
ib_create_qp() from double prints and unclear exit paths.

Reported-by: Parav Pandit <parav@mellanox.com>
Fixes: d291f1a6

 ("IB/core: Enforce PKey security on QPs")
Signed-off-by: Yuval Avnery <yuvalav@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>