drm/i915/display: program audio CDCLK-TS for keepalives

drm/i915/display: program audio CDCLK-TS for keepalives

XE_LPD display adds support for display audio codec keepalive feature.
This feature works also when display codec is in D3 state and the audio
link is off (BCLK off). To enable this functionality, display driver
must update the AUD_TS_CDCLK_M/N registers whenever CDCLK is changed.
Actual timestamps are generated only when the audio codec driver
specifically enables the KeepAlive (KAE) feature.

This patch adds new hooks to intel_set_cdclk() in order to inform
display audio driver when CDCLK change is started and when it is
complete.

Bspec: 53679
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211021105915.4128635-1-kai.vehmanen@linux.intel.com