RDMA/cm: Send and receive ECE parameter over the wire

ECE parameters are exchanged through REQ->REP/SIDR_REP messages, this
patch adds the data to provide to other side of CMID communication
channel.

Link: https://lore.kernel.org/r/20200526103304.196371-5-leon@kernel.org


Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>