arm64: dts: lx2160a: add optee-tz node

Disabled by default in SoC dtsi and enables in board dts files.

Signed-off-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Signed-off-by: Li Yang <leoyang.li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>