ALSA: sis7019: Use guard() for mutex locks

Replace the manual mutex lock/unlock pairs with guard() for code
simplification.

Only code refactoring, and no behavior change.

Signed-off-by: Takashi Iwai <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

sound/pci/sis7019.c

···
 	/* Get the AC97 semaphore -- software first, so we don't spin
 	 * pounding out IO reads on the hardware semaphore...
 	 */
-	mutex_lock(&sis->ac97_mutex);
+	guard(mutex)(&sis->ac97_mutex);
 
 	count = 0xffff;
 	while ((inw(io + SIS_AC97_SEMA) & SIS_AC97_SEMA_BUSY) && --count)
···
 timeout_sema:
 	outl(SIS_AC97_SEMA_RELEASE, io + SIS_AC97_SEMA);
 timeout:
-	mutex_unlock(&sis->ac97_mutex);
-
 	if (!count) {
 		dev_err(&sis->pci->dev, "ac97 codec %d timeout cmd 0x%08x\n",
 					codec, cmd);