drm/amd/display: update audio wall clock programming

[why]
for audio on real TV issue.

[how]
-add wall clock programming for DPREF based when
Pixel clock is done by DP DTO.

Signed-off-by: Charlene Liu <Charlene.Liu@amd.com>
Reviewed-by: Chris Park <Chris.Park@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>