mlxsw: spectrum_trap: Store all trap policer data in one array

Instead of maintaining an array of policers and a linked list, only
maintain an array.

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