panel/ilitek-ili9322: 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-ili9322.c

···
 	int ret;
 	int i;
 
-	ili = devm_kzalloc(dev, sizeof(struct ili9322), GFP_KERNEL);
-	if (!ili)
-		return -ENOMEM;
+	ili = devm_drm_panel_alloc(dev, struct ili9322, panel,
+				   &ili9322_drm_funcs, DRM_MODE_CONNECTOR_DPI);
+	if (IS_ERR(ili))
+		return PTR_ERR(ili);
 
 	spi_set_drvdata(spi, ili);
 
···
 	} else {
 		ili->input = ili->conf->input;
 	}
-
-	drm_panel_init(&ili->panel, dev, &ili9322_drm_funcs,
-		       DRM_MODE_CONNECTOR_DPI);
 
 	drm_panel_add(&ili->panel);