ALSA: hda - Add hdaudio bus modalias support

This patch just adds modalias sysfs entry to each hdaudio bus entry.

[rewritten to call the common helper function by tiwai]
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Reviewed-by: Vinod Koul <vinod.koul@intel.com>
Tested-by: Subhransu S Prusty <subhransu.s.prusty@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/hda/hdac_sysfs.c

@@ -45,6 +45,13 @@ CODEC_ATTR(mfg);
 CODEC_ATTR_STR(vendor_name);
 CODEC_ATTR_STR(chip_name);
 
+static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	return snd_hdac_codec_modalias(dev_to_hdac_dev(dev), buf, 256);
+}
+static DEVICE_ATTR_RO(modalias);
+
 static struct attribute *hdac_dev_attrs[] = {
 	&dev_attr_type.attr,
 	&dev_attr_vendor_id.attr,
@@ -54,6 +61,7 @@ static struct attribute *hdac_dev_attrs[] = {
 	&dev_attr_mfg.attr,
 	&dev_attr_vendor_name.attr,
 	&dev_attr_chip_name.attr,
+	&dev_attr_modalias.attr,
 	NULL
 };