arm64: dts: lx2160a: add dts for CEX7 platforms

arm64: dts: lx2160a: add dts for CEX7 platforms

The device tree enables the following features -
1. dpmac17 RGMII MAC connected to Atheros AR8035 phy
2. 2x MDIO busses
3. 2x USB 3.0 controllers
4. 4x SATA ports
5. MT35X 512Mb SPI flash
6. Temperature sensor on i2c0 channel 3
7. AMC6821 temperature and PWM fan controller (not fitted)

The module supports AMC6821 PWM controller which is not currently
assembled on currently available Com Express 7 hardware.

This commit adds support for the Clearfog CX and Honeycomb variants,
which are indentical in this patch, but once QSFP support is finished,
only the Clearfog CX will have a QSFP description.

Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>
[Add Makefile patch, split into clearfog-cx and honeycomb variants,
reworded commit -- rmk]
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>