linux-wandboard

MMFMWK-7806: drm: imx: dcss: check up/down scale ratios

When scaling up/down, DCSS has limits that cannot be exceeded. This
patch adds checks before the plane is updated and rejects those planes
that exceed the up/down scale limits.

Currently, the limit is 3:1 for downscaling and 1:3 for upscaling for
both video and graphics channels.

When support for WR_SCL/RD_SRC will be added, these limits will increase
to the following values:
 * video: 7:1 downscale, 1:7 upscale
 * graphics: 5:1 downscale, 1:5 upscale

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@nxp.com>