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/Kconfig b/Kconfig
index 92a8a69..4462432 100644
--- a/Kconfig
+++ b/Kconfig
@@ -321,7 +321,7 @@
 	default "u-boot-with-spl.sfp" if TARGET_SOCFPGA_GEN5
 	default "u-boot-spl.kwb" if ARCH_MVEBU && SPL
 	default "u-boot-elf.srec" if RCAR_GEN3
-	default "u-boot.itb" if SPL_LOAD_FIT && (ARCH_ROCKCHIP || \
+	default "u-boot.itb" if !BINMAN && SPL_LOAD_FIT && (ARCH_ROCKCHIP || \
 				ARCH_SUNXI || RISCV || ARCH_ZYNQMP)
 	default "u-boot.kwb" if ARCH_KIRKWOOD
 	default "u-boot-with-spl.bin" if ARCH_AT91 && SPL_NAND_SUPPORT