drm/panel: boe-tv101wum-nl6: make use of prepare_prev_first

The panel on sc7180-trogdor-wormdingler and
sc7180-trogdor-quackingstick hasn't been coming up since commit
9e15123e ("drm/msm/dsi: Stop unconditionally powering up DSI hosts
at modeset"). Let's add "prepare_prev_first" as has been done for many
other DSI panels.

Fixes: 9e15123e ("drm/msm/dsi: Stop unconditionally powering up DSI hosts at modeset")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Link: https://lore.kernel.org/r/20240216123111.1.I71c103720909790e1ec5a3f5bd96b18ab7b596fa@changeidSigned-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240216123111.1.I71c103720909790e1ec5a3f5bd96b18ab7b596fa@changeid

drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c

@@ -1871,6 +1871,8 @@ static int boe_panel_add(struct boe_panel *boe)
 
 	gpiod_set_value(boe->enable_gpio, 0);
 
+	boe->base.prepare_prev_first = true;
+
 	drm_panel_init(&boe->base, dev, &boe_panel_funcs,
 		       DRM_MODE_CONNECTOR_DSI);
 	err = of_drm_get_panel_orientation(dev->of_node, &boe->orientation);