drm/amd/display: Enable otg synchronization logic for DCN321

[Why]
Tiled display cannot synchronize properly after S3.
The fix for commit 5f0c7491 ("drm/amd/display: Fix for otg
synchronization logic") is not enable in DCN321, which causes
the otg is excluded from synchronization.

[How]
Enable otg synchronization logic in dcn321.

Fixes: 5f0c7491 ("drm/amd/display: Fix for otg synchronization logic")
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Loan Chen <lo-an.chen@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>