gpu: ipu-v3: Add chroma plane offset overrides to ipu_cpmem_set_image()

Allow the caller of ipu_cpmem_set_image() to override the latters
calculation of the chroma plane offsets, by adding override U/V
plane offsets to 'struct ipu_image'.

Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>