RDMA/mthca: Fix crash when polling CQ for shared QPs

Commit 21c2fe94 ("RDMA/mthca: Combine special QP struct with mthca QP")
introduced a new struct mthca_sqp which doesn't contain struct mthca_qp
any longer. Placing a pointer of this new struct into qptable leads
to crashes, because mthca_poll_one() expects a qp pointer. Fix this
by putting the correct pointer into qptable.

Fixes: 21c2fe94 ("RDMA/mthca: Combine special QP struct with mthca QP")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Link: https://lore.kernel.org/r/20230713141658.9426-1-tbogendoerfer@suse.deSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/mthca/mthca_qp.c

@@ -1393,7 +1393,7 @@ int mthca_alloc_sqp(struct mthca_dev *dev,
 	if (mthca_array_get(&dev->qp_table.qp, mqpn))
 		err = -EBUSY;
 	else
-		mthca_array_set(&dev->qp_table.qp, mqpn, qp->sqp);
+		mthca_array_set(&dev->qp_table.qp, mqpn, qp);
 	spin_unlock_irq(&dev->qp_table.lock);
 
 	if (err)