rockchip: Convert evb-rk3288 over to use binman

At present this board uses a custom script to produce the .its file.
Update it to use binman instead. Binman can create all the images that
are needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/evb-rk3288_defconfig b/configs/evb-rk3288_defconfig
index 6bdcc85..66bc387 100644
--- a/configs/evb-rk3288_defconfig
+++ b/configs/evb-rk3288_defconfig
@@ -15,7 +15,7 @@
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_SPL_LOAD_FIT=y
-CONFIG_SPL_FIT_GENERATOR="arch/arm/mach-rockchip/fit_spl_optee.sh"
+# CONFIG_USE_SPL_FIT_GENERATOR is not set
 CONFIG_USE_PREBOOT=y
 CONFIG_SILENT_CONSOLE=y
 CONFIG_DEFAULT_FDT_FILE="rk3288-evb-rk808.dtb"