rockchip: rk3188: Add Radxa Rock board

The Rock is a RK3188 based single board computer by Radxa.
Currently it still relies on the proprietary DDR init and
cannot use the generic SPL, but at least is able to boot
a linux kernel and system up to a regular login prompt.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>
Fix sort order in defconfig, enable CONFIG_SPL_TINY_MEMSET:
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-rockchip/rk3188/Kconfig b/arch/arm/mach-rockchip/rk3188/Kconfig
index b70d45c..d129fcd 100644
--- a/arch/arm/mach-rockchip/rk3188/Kconfig
+++ b/arch/arm/mach-rockchip/rk3188/Kconfig
@@ -1,5 +1,14 @@
 if ROCKCHIP_RK3188
 
+config TARGET_ROCK
+	bool "Radxa Rock"
+	help
+	  Rock is a RK3188-based development board with 2 USB and 1 otg
+	  ports, HDMI, TV-out, micro-SD card, audio, WiFi  and 100MBit
+	  Ethernet, It also includes on-board nand and 1GB of SDRAM.
+	  Expansion connectors provide access to display pins, I2C, SPI,
+	  UART and GPIOs.
+
 config SYS_SOC
 	default "rockchip"
 
@@ -24,4 +33,6 @@
 config TPL_SERIAL_SUPPORT
 	default y
 
+source "board/radxa/rock/Kconfig"
+
 endif