Peer to peer support was never implemented, so delete it to make code less
clutter.

Link: https://lore.kernel.org/r/20200310091438.248429-6-leon@kernel.orgSigned-off-by: NLeon Romanovsky <leonro@mellanox.com>
Reviewed-by: NMark Zhang <markz@mellanox.com>
Signed-off-by: NJason Gunthorpe <jgg@mellanox.com>