staging: imx-drm: Update TODO

The device tree bindings are updated regardless of the common display
framework and in the meantime the HDMI driver was included.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/staging/imx-drm/TODO

 TODO:
 - get DRM Maintainer review for this code
-- Wait for common display framework to hit mainline and update the IPU
-  driver to use it. This will most probably make changes to the devicetree
-  bindings necessary.
-- Factor out more code to common helper functions
 - decide where to put the base driver. It is not specific to a subsystem
   and would be used by DRM/KMS and media/V4L2
 
 Missing features (not necessarily for moving out of staging):
 
-- Add i.MX6 HDMI support
 - Add support for IC (Image converter)
 - Add support for CSI (CMOS Sensor interface)
 - Add support for VDIC (Video Deinterlacer)