Bring in the Mellanox implementation of iSER (iSCSI over RDMA) initiator,
written by Sagi Grimberg <sagig at mellanox.com> and Max Gurtovoy
<maxg at mellanox.com>.

This code comes from https://github.com/sagigrimberg/iser-freebsd, branch
iser-rebase-11-current-r291993. It's not connected to the build just yet;
it still needs some tweaks to adapt to my changes to iSCSI infrastructure.

Big thanks to Mellanox for their support for FreeBSD!

Obtained from: Mellanox Technologies
MFC after: 1 month
Relnotes: yes