gpu: ipu-v3: Add Camera Sensor Interface unit

Adds the Camera Sensor Interface (CSI) unit required for video capture.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Removed the unused clk_get_rate in ipu_csi_init_interface and the
ipu_csi_ccir_err_detection_enable/disable functions.
Checkpatch cleanup.

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