IB/mlx5: Update the supported DEVX commands

Update the supported DEVX commands, it includes adding to the
query/modify command's list and to the encoding handling.

In addition, a valid range for general commands was added to be used for
future commands.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Artemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>