drm/amd/display: reprogram det size while seamless boot

drm/amd/display: reprogram det size while seamless boot

[Why]
During system boot in second screen only mode on a seamless boot system,
there is a chance that the pipe's det size might not be reset.

[How]
Reset the det size while resetting the pipe during seamless boot.

Reviewed-by: Dmytro Laktyushkin <dmytro.laktyushkin@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Hugo Hu <hugo.hu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>