rockchip: add support for rk3288 miniarm board

Miniarm is a rockchip rk3288 based development board, which has lots of
interface such as HDMI, USB, micro-SD card, Audio etc.

Signed-off-by: Ziyuan Xu <xzy.xu@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.rockchip b/doc/README.rockchip
index 1b3a602..69b926c 100644
--- a/doc/README.rockchip
+++ b/doc/README.rockchip
@@ -36,14 +36,15 @@
 Building
 ========
 
-At present six RK3288 boards are supported:
+At present seven RK3288 boards are supported:
 
-   - Firefly RK3288 - use firefly-rk3288 configuration
-   - Radxa Rock 2 - use rock2 configuration
-   - Hisense Chromebook - use chromebook_jerry configuration
    - EVB RK3288 - use evb-rk3288 configuration
    - Fennec RK3288 - use fennec-rk3288 configuration
+   - Firefly RK3288 - use firefly-rk3288 configuration
+   - Hisense Chromebook - use chromebook_jerry configuration
+   - Miniarm RK3288 - use miniarm-rk3288 configuration
    - PopMetal RK3288 - use popmetal-rk3288 configuration
+   - Radxa Rock 2 - use rock2 configuration
 
 Two RK3036 board are supported: