ALSA: hda - Add a common helper to give the codec modalias string

This patch provide a new common helper function,
snd_hdac_codec_modalias(), to give the codec modalias name string.
This function will be used by multiple places in the later patches.

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>
diff --git a/include/sound/hdaudio.h b/include/sound/hdaudio.h
index ddca48e..e2b712c 100644
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -109,6 +109,7 @@
 int snd_hdac_device_register(struct hdac_device *codec);
 void snd_hdac_device_unregister(struct hdac_device *codec);
 int snd_hdac_device_set_chip_name(struct hdac_device *codec, const char *name);
+int snd_hdac_codec_modalias(struct hdac_device *hdac, char *buf, size_t size);
 
 int snd_hdac_refresh_widgets(struct hdac_device *codec);
 int snd_hdac_refresh_widget_sysfs(struct hdac_device *codec);