Fix multilist_create() memory leak

In arc_state_fini() the arc_l2c_only->arcs_list[*] multilists
must be destroyed. This accidentally regressed in d3c2ae1c.

Reviewed by: Tom Caputi <tcaputi@datto.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #5151
Closes #5152