In ASoC driver, snd_hdac_device_register() will be called by
snd_hdac_ext_bus_device_init() and snd_hdac_device_unregister()
will called by snd_hdac_ext_bus_device_remove(). However when
ASoC codec driver call snd_hda_codec_device_new() to create a
new hda codec, it will assign snd_hda_codec_dev_free() to the
dev_free ops and snd_hda_codec_dev_free() will call
snd_hdac_device_unregister(). As a result, snd_hdac_device_unregister()
will be called twice in ASoC driver. To prevent it, we use hdev
type to determine if the hda codec is registered by legacy HDA
driver or ASoC driver and unregister device in  snd_hda_codec_dev_free()
only if it is a legacy HDA device.
This patch will overwrite the hdev type so that we can know it is
a ASoC device.
Signed-off-by: Bard liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>