arm: imx: imx8m: add optee configuration to ft_system_setup

If optee is detected configure it in the Linux device-tree:
 - add /firmware/optee node
 - add /reserved-memory nodes for optee_core and optee_shm

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>