rockchip: add basic support for fennec-rk3288 board

Fennec is a RK3288-based development board with 2 USB ports, HDMI,
micro-SD card, audio and WiFi and Gigabit Ethernet. It also includes
on-board 8GB eMMC and 2GB of SDRAM. Expansion connectors provides access
to display pins, I2C, SPI, UART and GPIOs.

Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
12 files changed