rockchip: Add support for Raxda Rock 2

This board includes an RK3288 SoC on a SOM. It can be mounted on a
base-board which provides a wide range of peripherals.

So far this is verified to boot to a prompt from a microSD card. The serial
console works as well as HDMI.

Thanks to Tom Cubie for sending me a board.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/README.rockchip b/doc/README.rockchip
index 7be5a13..364affd 100644
--- a/doc/README.rockchip
+++ b/doc/README.rockchip
@@ -39,7 +39,7 @@
 At present three RK3288 boards are supported:
 
    - Firefly RK3288 - use firefly-rk3288 configuration
-   - Radxa Rock 2 - also uses firefly-rk3288 configuration
+   - Radxa Rock 2 - use rock2 configuration
    - Haier Chromebook - use chromebook_jerry configuration
 
 one RK3036 board is support:
@@ -52,11 +52,6 @@
 
 (or you can use another cross compiler if you prefer)
 
-Note that the Radxa Rock 2 uses the Firefly configuration for now as
-device tree files are not yet available for the Rock 2. Clearly the two
-have hardware differences, so this approach will break down as more drivers
-are added.
-
 
 Writing to the board with USB
 =============================