RDMA/siw: Fix post_recv QP state locking

Do not release qp state lock if not previously acquired.

Fixes: cf049bb3 ("RDMA/siw: Fix SQ/RQ drain logic")
Link: https://lore.kernel.org/r/20191025142903.20625-1-bmt@zurich.ibm.comReported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bernard Metzler <bmt@zurich.ibm.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/siw/siw_verbs.c

@@ -990,7 +990,6 @@ int siw_post_receive(struct ib_qp *base_qp, const struct ib_recv_wr *wr,
 	}
 	if (!qp->kernel_verbs) {
 		siw_dbg_qp(qp, "no kernel post_recv for user mapped sq\n");
-		up_read(&qp->state_lock);
 		*bad_wr = wr;
 		return -EINVAL;
 	}