RDMA/ocrdma: Fix an error code in ocrdma_alloc_pd()

We should preserve the original "status" error code instead of resetting
it to zero.  Returning ERR_PTR(0) is the same as NULL and results in a
NULL dereference in the callers.  I added a printk() on error instead.

Fixes: 45e86b33ec8b ("RDMA/ocrdma: Cache recv DB until QP moved to RTR")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/ocrdma/ocrdma_verbs.c

@@ -744,7 +744,8 @@ err:
 	if (is_uctx_pd) {
 		ocrdma_release_ucontext_pd(uctx);
 	} else {
-		status = _ocrdma_dealloc_pd(dev, pd);
+		if (_ocrdma_dealloc_pd(dev, pd))
+			pr_err("%s: _ocrdma_dealloc_pd() failed\n", __func__);
 	}
 exit:
 	return ERR_PTR(status);