rockchip: Add basic support for evb-rk3036 board

This add some basic files required to allow the board to dispaly
serial message and can run command(mmc info etc)

Signed-off-by: Lin Huang <hl@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
Moved board Kconfig fragment from previous patch into this one to fix
build error:
Signed-off-by: Simon Glass <sjg@chromium.org>

Series-changes: 8
- moved board Kconfig fragment from previous patch into this one