ALSA: hda - Kill snd_hda_codec_update_cache()

snd_hda_codec_update_cache() used to serve for a slightly different
purpose from snd_hdac_write_cache(), but now both of them became
identical.

Let's unify and replace with the latter one consistently.

Signed-off-by: Takashi Iwai <tiwai@suse.de>