IB/mlx5: Add Scatter FCS support for Raw Packet QP

Enable Scatter FCS in the RQ context when the user passes
Scatter FCS create flag.

Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>