tests: Fix mlx5dr dest port test

[ Upstream commit f2c2c4a ]

Fix mlx5dr dest port test by adding polling after recv on
the QP.

Fixes: 7f5e004 ("tests: Add coverage for DR VPort and IBPort actions")
Signed-off-by: Ido Kalir <idok@nvidia.com>
Signed-off-by: Edward Srouji <edwards@nvidia.com>
Signed-off-by: Nicolas Morey-Chaisemartin <nmoreychaisemartin@suse.com>

tests/test_mlx5_dr.py

@@ -231,6 +231,7 @@ def send_server_fdb_to_nic_packets(self, iters):
         for _ in range(iters):
             u.send(self.server, c_send_wr, e.IBV_WR_SEND)
             u.poll_cq_ex(self.server.cq)
+            u.poll_cq_ex(self.server.cq)
             u.post_recv(self.server, s_recv_wr, qp_idx=0)
             msg_received = self.server.mr.read(self.server.msg_size, 0)
             u.validate_raw(msg_received, msg, [])