ALSA: virtuoso: do not use fast I2C speed

To make the I2C communication reliable when using the H6 daughterboard,
reduce the I2C clock frequency.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/oxygen/xonar_pcm179x.c b/sound/pci/oxygen/xonar_pcm179x.c
index 5ec8be3..49898d3 100644
--- a/sound/pci/oxygen/xonar_pcm179x.c
+++ b/sound/pci/oxygen/xonar_pcm179x.c
@@ -374,7 +374,7 @@
 	oxygen_write16(chip, OXYGEN_2WIRE_BUS_STATUS,
 		       OXYGEN_2WIRE_LENGTH_8 |
 		       OXYGEN_2WIRE_INTERRUPT_MASK |
-		       OXYGEN_2WIRE_SPEED_FAST);
+		       OXYGEN_2WIRE_SPEED_STANDARD);
 
 	data->pcm179x.generic.anti_pop_delay = 100;
 	data->pcm179x.generic.output_enable_bit = GPIO_HDAV_OUTPUT_ENABLE;
@@ -403,7 +403,7 @@
 	oxygen_write16(chip, OXYGEN_2WIRE_BUS_STATUS,
 		       OXYGEN_2WIRE_LENGTH_8 |
 		       OXYGEN_2WIRE_INTERRUPT_MASK |
-		       OXYGEN_2WIRE_SPEED_FAST);
+		       OXYGEN_2WIRE_SPEED_STANDARD);
 }
 
 static void xonar_st_init_common(struct oxygen *chip)