gpu: ipu-v3: Add Image Converter unit

Adds the Image Converter (IC) unit.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>

Condensed the three CSC setup functions into a single one that
uses static tables to set up the CSC task parameters.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>