net/mlx5: fix queue rollback when starting device

net/mlx5: fix queue rollback when starting device

mlx5_rxq_start() and mlx5_rxq_stop() must be strictly paired because
internal reference counter is increased or decreased inside. Also,
mlx5_rxq_get() must be paired with mlx5_rxq_release().

Fixes: 7d6bf6b866b8 ("net/mlx5: add Multi-Packet Rx support")
Fixes: a1366b1a2be3 ("net/mlx5: add reference counter on DPDK Rx queues")
Fixes: 6e78005a9b30 ("net/mlx5: add reference counter on DPDK Tx queues")
Cc: stable@dpdk.org
Signed-off-by: Yongseok Koh <yskoh@mellanox.com>