drm/i915/audio: Precompute the ELD

Stash the ELD into the crtc_state and precompute it. This gets
rid of the ugly ELD mutation during intel_audio_codec_enable(),
and opens the door for the state checker.

v2: Make another copy for the acomp hooks (Chaitanya)
    Split out the bogus ELD handling change (Jani)

Cc: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Cc: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Jani Nikula <jani.nikula@intel.com> #v1
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230124144628.4649-5-ville.syrjala@linux.intel.com