net/mlx5: fix Multi-Packet RQ mempool name

net/mlx5: fix Multi-Packet RQ mempool name

Currently, the name of MPRQ mempool is set by
	snprintf(name, sizeof(name), "%s-mprq", dev->device->name);
For port representor, the name is duplicate of its master and failed to
create such a mempool having the same name. Port ID is used in the name
instead.

Fixes: 7d6bf6b866b8 ("net/mlx5: add Multi-Packet Rx support")
Cc: stable@dpdk.org
Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
Acked-by: Shahaf Shuler <shahafs@mellanox.com>