mlxsw: spectrum: drop useless LIST_HEAD

mlxsw: spectrum: drop useless LIST_HEAD

Drop LIST_HEAD where the variable it declares is never used.

The uses were removed in 244cd96adb5f ("net_sched: remove
list_head from tc_action"), but not the declaration.

The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier x;
@@
- LIST_HEAD(x);
  ... when != x
// </smpl>

Fixes: 244cd96adb5f ("net_sched: remove list_head from tc_action")
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>