drm/amd/display: Reduce redundant minimal transitions due to SubVP

[WHY]
Stream ID's associated with phantom pipes can change often as they
are reconstructed on full updates, however they can remain identical
depending on the required update.

[HOW]
In the case phantom streams and pipe topologies remain the same
between updates, mark the transition as seamless.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>