ALSA: hda: Intel: enable automatic runtime pm for HDMI codecs by default

Enable runtime PM of the HDMI audio codec on the latest Intel platforms.
So the HD-A controller or HDMI codec can suspend when idle timeout by
default and release the GFX power well.
The patch influences HSW/BDW/BYT/BSW/SKL. Eariler platforms and third
party analog codecs will not be influenced.

Signed-off-by: Lu, Han <han.lu@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_hdmi.c

@@ -2356,6 +2356,10 @@ static int patch_generic_hdmi(struct hda_codec *codec)
 		codec->dp_mst = true;
 	}
 
+	/* Enable runtime pm for HDMI audio codec of HSW/BDW/SKL/BYT/BSW */
+	if (is_haswell_plus(codec) || is_valleyview_plus(codec))
+		codec->auto_runtime_pm = 1;
+
 	generic_hdmi_init_per_pins(codec);
 
 	init_channel_allocations();