IB/mlx5: Support creation of a WQ with scatter FCS offload

Add support for creation of a WQ with scatter FCS capability, if
this capability is supported by the hardware.

Signed-off-by: Noa Osherovich <noaos@mellanox.com>
Reviewed-by: Majd Dibbiny <majd@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>