[ALSA] insert set_current_state() before schedule_timeout()

Wavefront drivers
Insert set_current_state() before schedule_timeout(). Without the
insertion, schedule_timeout() returns immediately, resulting in an
effective busy-wait.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/wavefront/wavefront_synth.c

@@ -1751,6 +1751,7 @@ wavefront_should_cause_interrupt (snd_wavefront_t *dev,
 	outb (val,port);
 	spin_unlock_irq(&dev->irq_lock);
 	while (1) {
+		set_current_state(TASK_INTERRUPTIBLE);
 		if ((timeout = schedule_timeout(timeout)) == 0)
 			return;
 		if (dev->irq_ok)