rockchip: Enable building a SPI ROM image on bob

Add a simple binman config and enable CONFIG_HAS_ROM so that U-Boot
produces a ROM for bob.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-rockchip/rk3399/Kconfig b/arch/arm/mach-rockchip/rk3399/Kconfig
index 254b9c5..17628f9 100644
--- a/arch/arm/mach-rockchip/rk3399/Kconfig
+++ b/arch/arm/mach-rockchip/rk3399/Kconfig
@@ -5,6 +5,8 @@
 
 config TARGET_CHROMEBOOK_BOB
 	bool "Asus Flip C101PA Chromebook (RK3399)"
+	select HAS_ROM
+	select ROCKCHIP_SPI_IMAGE
 	help
 	  Bob is a small RK3299-based device similar in apperance to Minnie.
 	  It has two USB 3.0 type-C ports, 4GB of SDRAM, WiFi and a 10.1",