drm/amd/display: Remove dc_stream_state->status

[Why]
dc_state has an array of dc_stream_status that contain
pointers to the dc_plane_state and other useful information

Confusingly, dc_stream_state also contains a dc_stream_status
called status.  This struct was partially initialized and
used in a few places

[How]
stream->status.link has been replaced with stream->sink->link.
If a stream does not have a sink, or a sink does not have a link,
something has gone seriously wrong

All other properties of stream->status were zeroed by kzalloc
and never initialized, so they have been replaced by the number 0

This is a refactor: no functional change is intended

Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Acked-by: Tony Cheng <Tony.Cheng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>