ALSA: pcm: fix lost wakeup event scenarios in snd_pcm_drain

lost wakeup can occur after enabling irq, therefore put task
into interruptible before enabling interrupts,

without this change, task can be put to sleep and snd_pcm_drain
will delay

Fixes: f2b3614c ("ALSA: PCM - Don't check DMA time-out too shortly")
Signed-off-by: Yuki Tsunashima <ytsunashima@jp.adit-jv.com>
Signed-off-by: Suresh Udipi <sudipi@jp.adit-jv.com>
[ported from 4.9]
Signed-off-by: Adam Miartus <amiartus@de.adit-jv.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>