iwlwifi: remove unused work structs

	struct workqueue_struct *workqueue;

	struct work_struct restart;

	struct work_struct calibrated_work;

	struct work_struct scan_completed;

	struct work_struct rx_replenish;

	struct work_struct abort_scan;

	struct work_struct update_link_led;

	struct work_struct auth_work;

	struct work_struct report_work;

	struct work_struct request_scan;

	struct work_struct beacon_update;

	struct work_struct tt_work;