media: ipu3-cio2: Rename CIO2_IMAGE_MAX_LENGTH as CIO2_IMAGE_MAX_HEIGHT

CIO2_IMAGE_MAX_LENGTH is the maximum height of the image. Rename it as
"CIO2_IMAGE_MAX_HEIGHT" in order to better describe what it is.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>