Generally speaking, these is no Mellanox driver available that supports ConnectX-2 over Esxi6.0
However, the latest Mellanox driver that supports ConnectX-2 adapter is mlnx_ofed_esxi v18.104.22.168, over Esxi5.5 with fw v2.9.1200 and above.
See in Mellanox web-site: http://www.mellanox.com/page/products_dyn?product_family=29
I doubt whether VMware have any inbox driver that may supports ConnectX-2 EN adapter over Esxi6.0 but you can try to get they advice on this as well
Notice that Mellanox has already declared ConnectX-2 EN MNPA19-XTR network adapter as EOL (end-of-life) therefore Mellanox is not providing any support related to this card.