rockchip: Fix the configuration for chromebook_jerry

Various updates did not make it through to this board. Also the instructions
for building a SPI image are no-longer correct. Fix these so that Jerry can
boot to a prompt again.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/chromebook_jerry.h b/include/configs/chromebook_jerry.h
index 058325c..e29d776 100644
--- a/include/configs/chromebook_jerry.h
+++ b/include/configs/chromebook_jerry.h
@@ -13,5 +13,6 @@
 #define CONFIG_SPL_SPI_SUPPORT
 #define CONFIG_SPL_SPI_FLASH_SUPPORT
 #define CONFIG_SPL_SPI_LOAD
+#define CONFIG_SPI_FLASH_GIGADEVICE
 
 #endif