drm/imx: various cleanups
- Switch to drm_*_get/put() helpers
- Use correct parallel-display connector enum: DPI instead of VGA
- Remove incorrect unit name from device tree binding documentation example
- Remove an unused variable
* tag 'imx-drm-next-2017-10-18' of git://git.pengutronix.de/git/pza/linux:
gpu: ipu-v3: ipu-dc: Remove unused 'di' variable
dt-bindings: fsl-imx-drm: Remove incorrect "@di0" usage
drm/imx: parallel-display: use correct connector enum
drm/imx: switch to drm_*_get(), drm_*_put() helpers