drm/mediatek: Add DPI sub driver

[Dan Carpenter]

Hello Jie Qiu,

This is a semi-automatic email about new static checker warnings.

The patch 9e629c17aa8d: "drm/mediatek: Add DPI sub driver" from Jan 
4, 2016, leads to the following Smatch complaint:

drivers/gpu/drm/mediatek/mtk_dpi.c:436 mtk_dpi_set_display_mode()
	 error: we previously assumed 'dpi' could be null (see line 435)

drivers/gpu/drm/mediatek/mtk_dpi.c
   434	
   435		if (!dpi) {
                    ^^^^
Check.

   436			dev_err(dpi->dev, "invalid argument\n");
                                ^^^^^^^^^
Deref.  Can dpi even be NULL, btw?

   437			return -EINVAL;
   438		}

regards,
dan carpenter