Blackhole Ethernet tiles

[gangwon]

The blackhole_140_arch.yaml descriptor defines 14 Ethernet tiles, but aren't there actually 10 Ethernet interfaces? I'm curios about the relationship between the 10 interfaces and the tiles. (For example, perhaps only 10 tiles are connected to the NoC, while the remaining 4 physically include Ethernet cores but serve only as routers in the NoC?)