gpu: ipu-v3: Add ipu_rot_mode_is_irt()

Add a macro that returns boolean true if the given ipu_rotate_mode
requires the use of the Image Rotator.

Signed-off-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>