drm/amd/display: add seamless boot flag to stream

[Why]
If we determine the stream we are trying to commit
matches HW, we want to try to optimize.

[How]
Try to acquire the HW resources that are already enabled
and optimize.
Also skip backend reprogramming

Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>