drm/amd/display: Re-check seamless boot can be enabled or not

drm/amd/display: Re-check seamless boot can be enabled or not

[Why]
If the seamless boot feature has already been enabled, and
dc_commit_streams is called again before receiving a flip, the
driver will adjust the engine clock without turning off the screen,
which will cause garbage to occur. However, in reality, the Pixel
Clock from the first dc_commit_streams and the second dc_commit_streams
are different.

[How]
If the apply seamless boot flag in the previous stream has not been
cleared, and dc_commit_streams is received again, we need to recheck
whether seamless boot should be disabled

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Paul Hsieh <Paul.Hsieh@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>