ALSA: pcxhr - add support for gpio ports and minor bug fix

- add support for gpio ports (2 GPI, 2 GPO) of pcxhr stereo cards
- minor bugfixes : allow setting clock to internal by the mixer
                   even if there is no stream (but monitoring)

Signed-off-by: Markus Bollinger <bollinger@digigram.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/pcxhr/pcxhr_mixer.c b/sound/pci/pcxhr/pcxhr_mixer.c
index 2436e37..fec0493 100644
--- a/sound/pci/pcxhr/pcxhr_mixer.c
+++ b/sound/pci/pcxhr/pcxhr_mixer.c
@@ -789,11 +789,15 @@
 	if (mgr->use_clock_type != ucontrol->value.enumerated.item[0]) {
 		mutex_lock(&mgr->setup_mutex);
 		mgr->use_clock_type = ucontrol->value.enumerated.item[0];
-		if (mgr->use_clock_type)
+		rate = 0;
+		if (mgr->use_clock_type != PCXHR_CLOCK_TYPE_INTERNAL) {
 			pcxhr_get_external_clock(mgr, mgr->use_clock_type,
 						 &rate);
-		else
+		} else {
 			rate = mgr->sample_rate;
+			if (!rate)
+				rate = 48000;
+		}
 		if (rate) {
 			pcxhr_set_clock(mgr, rate);
 			if (mgr->sample_rate)