rockchip: Enable building a SPI ROM image on jerry

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

Change the binman image definition to support multiple images, since it
may be used to build both u-boot-rockchip.bin and u-boot.rom

Signed-off-by: Simon Glass <sjg@chromium.org>
4 files changed