The initialization of async_handlers_list
was accidentally removed in a previous change.
Then it was restoted by commit 
175e69e33c66 ("wifi: iwlwifi: restore
missing initialization of async_handlers_list").
Somehow, the initialization disappeared again.
Restote it.
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
 
        /* Setup async RX handling */
        spin_lock_init(&mld->async_handlers_lock);
+       INIT_LIST_HEAD(&mld->async_handlers_list);
        wiphy_work_init(&mld->async_handlers_wk,
                        iwl_mld_async_handlers_wk);