ALSA: usb-audio: Use auto-cleanup for shutdown locks

ALSA: usb-audio: Use auto-cleanup for shutdown locks

Introduce an auto-cleanup macro for the temporary shutdown locks for
USB-audio, and replace the manual lock/unlock pairs with it.

Namely, the former

	err = snd_usb_lock_shutdown(chip);
	if (err < 0)
		return err;
	....
	snd_usb_unlock_shutdown(chip);

is replaced with

	CLASS(snd_usb_lock, pm)(chip);
	if (pm.err < 0)
		return pm.err;
	....

with the automatic unlocking.

Link: https://patch.msgid.link/20250811101647.8637-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>