Enable user application to add rules for RDMA TX steering table.
Rules in this steering table will allow to steer transmitted RDMA
traffic.

Link: https://lore.kernel.org/r/20200324061425.1570190-3-leon@kernel.orgSigned-off-by: Michael Guralnik <michaelgur@mellanox.com>
Reviewed-by: Maor Gottlieb <maorg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>