netdevsim: add ACL trap reporting cookie as a metadata

Add new trap ACL which reports flow action cookie in a metadata. Allow
used to setup the cookie using debugfs file.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>