linux-phytec-fsl

arm64: dts: Add ZTE ZX296718 SoC dts and Makefile

Add device tree support for ZX296718 SoC and evaluation board based
on it.  Also document new values.

Signed-off-by: Jun Nie <jun.nie@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>