drm/amd/display: Enable fast update for DCN314

[Why & How]
Enable legacy fast update for DCN314
Acked-by: Wayne Lin <wayne.lin@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/resource/dcn314/dcn314_resource.c

@@ -925,6 +925,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	},
 
 	.seamless_boot_odm_combine = true,
+	.enable_legacy_fast_update = true,
 	.using_dml2 = false,
 };