panel/ilitek-ili9881c: Use refcounted allocation in place of devm_kzalloc()

Move to using the new API devm_drm_panel_alloc() to allocate the
panel.

Reviewed-by: Neil Armstrong <[e-mail]>
Signed-off-by: Anusha Srivatsa <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Maxime Ripard <[e-mail]>

drivers/gpu/drm/panel/panel-ilitek-ili9881c.c

···
 	struct ili9881c *ctx;
 	int ret;
 
-	ctx = devm_kzalloc(&dsi->dev, sizeof(*ctx), GFP_KERNEL);
-	if (!ctx)
-		return -ENOMEM;
+	ctx = devm_drm_panel_alloc(&dsi->dev, struct ili9881c, panel, &ili9881c_funcs,
+				   DRM_MODE_CONNECTOR_DSI);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
 	mipi_dsi_set_drvdata(dsi, ctx);
 	ctx->dsi = dsi;
 	ctx->desc = of_device_get_match_data(&dsi->dev);
-
-	drm_panel_init(&ctx->panel, &dsi->dev, &ili9881c_funcs,
-		       DRM_MODE_CONNECTOR_DSI);
 
 	ctx->power = devm_regulator_get(&dsi->dev, "power");
 	if (IS_ERR(ctx->power))