drm/radeon: clean up audio dto programming

Split into DCE2/3 and DCE4/5 variants. Still todo is to
calculate the DTO dividers properly.  Add proper formula
to the comments.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
4 files changed