drm/imx/lcdc: fix a NULL vs IS_ERR() bug in probe

The devm_drm_dev_alloc() function returns error pointers. It never
returns NULL. Fix the check.

Fixes: c87e859cdeb5 ("drm/imx/lcdc: Implement DRM driver for imx25")
Signed-off-by: Dan Carpenter <[e-mail]>
Reviewed-by: Uwe Kleine-König <[e-mail]>
Signed-off-by: Javier Martinez Canillas <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/imx/lcdc/imx-lcdc.c

···
 
 	lcdc = devm_drm_dev_alloc(dev, &imx_lcdc_drm_driver,
 				  struct imx_lcdc, drm);
-	if (!lcdc)
-		return -ENOMEM;
+	if (IS_ERR(lcdc))
+		return PTR_ERR(lcdc);
 
 	drm = &lcdc->drm;