drm/panel: rm68200: No error msg if probe deferred

Do not print an error message if the regulator framework returns
EPROBE_DEFER.
Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1553155535-13555-1-git-send-email-yannick.fertre@st.com

drivers/gpu/drm/panel/panel-raydium-rm68200.c

@@ -383,7 +383,8 @@ static int rm68200_probe(struct mipi_dsi_device *dsi)
 	ctx->supply = devm_regulator_get(dev, "power");
 	if (IS_ERR(ctx->supply)) {
 		ret = PTR_ERR(ctx->supply);
-		dev_err(dev, "cannot get regulator: %d\n", ret);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "cannot get regulator: %d\n", ret);
 		return ret;
 	}