[ALSA] Fix substream selection in PCM and rawmidi

The PCM and rawmidi substreams can be selected explicitly by opening
control handle and set via *_PREFER_SUBDEVICE ioctl.  But, when
multiple controls are opened, the driver gets confused.
The patch fixes the initialization of prefer_*_subdevice and the
check of multiple controls.  The first set subdevice is picked up
as the valid one.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/core/rawmidi.c

diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 8a2bdfa..269c467 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -430,7 +430,8 @@
 			kctl = snd_ctl_file(list);
 			if (kctl->pid == current->pid) {
 				subdevice = kctl->prefer_rawmidi_subdevice;
-				break;
+				if (subdevice != -1)
+					break;
 			}
 		}
 		up_read(&card->controls_rwsem);