ARM64: dts: ls2080a: add device configuration node

Add the dts node for device configuration unit that provides
general purpose configuration and status for the device.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Scott Wood <oss@buserror.net>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>