firewire: normalize style of queue_work wrappers

A few stylistic changes to unify some code patterns in the subsystem:

  - The similar queue_delayed_work helpers fw_schedule_bm_work,
    schedule_iso_resource, and sbp2_queue_work now have the same call
    convention.
  - Two conditional calls of schedule_iso_resource are factored into
    another small helper.
  - An sbp2_target_get helper is added as counterpart to
    sbp2_target_put.

Object size of firewire-core is decreased a little bit, object size of
firewire-sbp2 remains unchanged.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/core-card.c

@@ -211,11 +211,8 @@ static const char gap_count_table[] = {
 
 void fw_schedule_bm_work(struct fw_card *card, unsigned long delay)
 {
-	int scheduled;
-
 	fw_card_get(card);
-	scheduled = schedule_delayed_work(&card->work, delay);
-	if (!scheduled)
+	if (!schedule_delayed_work(&card->work, delay))
 		fw_card_put(card);
 }