drm/amd/display: upstream link_dp_dpia_bw.c

[WHY & HOW]
- make link_dp_dpia_bw.c available for linux.
- add the verify link peak bw
- clean up code and comment format.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Mustapha Ghaddar <mghaddar@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>