ARM: dts: rockchip: add basic support for RK1108 SOC

RK1108 is embedded with an ARM Cortex-A7 single core and a DSP core.
It is designed for varies application scenario such as car DVR, sports
DV, secure camera and UAV camera.

This patch add basic support for it with DMAC / UART / CRU / pinctrl / MMC
enabled.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Tested-by: Jacob Chen <jacob2.chen@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>