drm/amd/display: Move wm and dlg calculation to FPU code

Move dcn32_calculate_wm_and_dlg from dcn32 resources to the FPU code.
Additionally, this commit adds an interface to it.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>