ALSA: x86: Rearrange defines

We have two header files and everything is mixed up chaotically.
Move the chip-specific definitions like the hardware registers to
intel_hdmi_lpe_audio.h, and the rest, the implementation specific
stuff into intel_hdmi_audio.h.

In addition, put some more comments to the register fields, and fix
the incorrect name prefix for AUD_HDMI_STATUS bits, too.

The whole changes are merely a code shuffling, and there is no
functional change.

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