Sparse reports a warning at tscm_hwdep_read_locked()

warning: context imbalance in tscm_hwdep_read_locked() - unexpected unlock

The root cause is the missing annotation at tscm_hwdep_read_locked()
Add the missing __releases(&tscm->lock) annotation
Signed-off-by: NJules Irenge <jbi.octave@gmail.com>
Acked-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200311010908.42366-9-jbi.octave@gmail.comSigned-off-by: NTakashi Iwai <tiwai@suse.de>