ALSA: seq: oss: Use scoped cleanup for temporary MIDI use lock

ALSA: seq: oss: Use scoped cleanup for temporary MIDI use lock

The OSS sequencer write and out-of-band paths may receive a temporary
snd_use_lock_t reference from snd_seq_oss_process_event(). This was added
to keep MIDI device data alive until events with embedded SysEx data are
dispatched.

Use a scoped cleanup helper for that temporary reference. This keeps the
lifetime rule local to the variable declaration and avoids future missing
snd_use_lock_free() paths if these event handling paths gain more exits.

No functional change is intended.

Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260604-alsa-scoped-cleanups-v1-3-10c43152a728@gmail.com