Add iMX8DX MEK DTS file and its rpmsg DTS file, both re-use the
common MEK board DTS files.
The 8DX MEK only has 1GB DDR, so decrease its CMA size to 320MB.
Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
(cherry picked from commit 9ab7b42c2c99dc0e2dd7fafa5cb4cebd792aceaf)
Ye Li