ALSA: jack: Use guard() for locking

[ Upstream commit 7234795b ]

We can simplify the code gracefully with new guard() macro and co for
automatic cleanup of locks.

Only the code refactoring, and no functional changes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240227085306.9764-11-tiwai@suse.de


Stable-dep-of: 495000a3 ("ALSA: core: Remove debugfs at disconnection")
Signed-off-by: Sasha Levin <sashal@kernel.org>