drm/amd/display: Improve the log precision

drm/amd/display: Improve the log precision

The previous assumption that there will be an optimize_bandwidth call
following every prepare_bandwidth call was incorrect and caused small
inaccuracies in logging, as some info was only updated in later prepare
calls.

Reviewed-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Ethan Bitnun <Ethan.Bitnun@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>