gva_rk3229: Update README document.

Change-Id: I423d625f4f92e4762a32162772f3858f8069723a
Signed-off-by: Cody Xie <cody.xie@rock-chips.com>

board/rockchip/gva_rk3229/README

@@ -9,6 +9,8 @@ Get the Source and prebuild binary
   > git clone https://github.com/rockchip-linux/rkdeveloptool.git
 
 Compile the OP-TEE
+(For Android Things Project, use the image bellow.
+<android root>/vendor/bsp/rockchip/security/optee/os/trust_with_ta.img)
 ===============
 
   > cd optee_os
@@ -18,6 +20,7 @@ Compile the OP-TEE
   > cp out/arm-plat-rockchip/core/tee-pager.bin ../u-boot/tee.bin
 
 Compile the U-Boot
+(For Android Things Project, use Android build system.)
 ==================
 
   > cd ../u-boot
@@ -31,11 +34,11 @@ Compile the U-Boot
 Compile the rkdeveloptool
 =======================
   Follow instructions in latest README
-  > cd ../rkflashtool
+  > cd ../rkdeveloptool
+  > sudo apt-get install libudev-dev libusb-1.0-0-dev dh-autoreconf
   > autoreconf -i
   > ./configure
   > make
-  > sudo make install
 
   Get rkdeveloptool in you Host in this step.
 
@@ -43,19 +46,23 @@ Both origin binaries and Tool are ready now, choose either option 1 or
 option 2 to deploy U-Boot.
 
 Package the image
+(For Android Things Project, use Android build system.)
 =================
 
   > cd ../u-boot
-  > rkbin/tools/loaderimage --pack --uboot u-boot-dtb.bin uboot.img
+  > rkbin/tools/loaderimage --pack --uboot u-boot-dtb.bin uboot.img 0x61000000
 
   Get uboot.img in this step.
 
 Flash the image to eMMC
+(For Android Things Project that supports AB update,
+please follow google's documents.)
 =======================
 Power on(or reset with RESET KEY) with MASKROM KEY preesed, and then:
   > cd ..
   > rkdeveloptool db rkbin/rk32/rk322x_loader_v1.04.232.bin
   > rkdeveloptool wl 0x4000 uboot.img
+  > rkdeveloptool wl 0x6000 trust.img
   > rkdeveloptool rd
 
 You should be able to get U-Boot log message with OP-TEE boot info.