RDMA/nes: Fill in firmware version for ethtool

Fill in firmware version for ethtool_drvinfo.

Signed-off-by: Sweta Bhatt <sweta.bhatt@einfochips.com>
Signed-off-by: Chien Tung <ctung@neteffect.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>