drm/amd/display: Enable legacy fast update for dcn301

Set up to enable legacy fast update.

Acked-by: Wayne Lin <[e-mail]>
Signed-off-by: Rodrigo Siqueira <[e-mail]>
Tested-by: Daniel Wheeler <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/dc/resource/dcn301/dcn301_resource.c

···
 	.dmub_command_table = true,
 	.use_max_lb = false,
 	.exit_idle_opt_for_cursor_updates = true,
+	.enable_legacy_fast_update = true,
 	.using_dml2 = false,
 };