firewire: core: use WARN_ON_ONCE() to avoid superfluous dumps

It is enough to notify programming mistakes to programmers just once.
Suggested-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240905131029.6433-1-o-takashi@sakamocchi.jpSigned-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

drivers/firewire/core-iso.c

@@ -220,7 +220,7 @@ int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 	might_sleep();
 
 	// Avoid dead lock due to programming mistake.
-	if (WARN_ON(current_work() == &ctx->work))
+	if (WARN_ON_ONCE(current_work() == &ctx->work))
 		return 0;
 
 	disable_work_sync(&ctx->work);
@@ -244,7 +244,7 @@ int fw_iso_context_stop(struct fw_iso_context *ctx)
 	might_sleep();
 
 	// Avoid dead lock due to programming mistake.
-	if (WARN_ON(current_work() == &ctx->work))
+	if (WARN_ON_ONCE(current_work() == &ctx->work))
 		return 0;
 
 	err = ctx->card->driver->stop_iso(ctx);