riscv: Select appropriate image type

Select between the 32-bit or 64-bit arch type for the image headers
depending on how the build is configured.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/arch/riscv/include/asm/u-boot.h b/arch/riscv/include/asm/u-boot.h
index d5e1d5f..a90cc4c 100644
--- a/arch/riscv/include/asm/u-boot.h
+++ b/arch/riscv/include/asm/u-boot.h
@@ -23,6 +23,10 @@
 #include <asm/u-boot-riscv.h>
 
 /* For image.h:image_check_target_arch() */
+#ifdef CONFIG_64BIT
+#define IH_ARCH_DEFAULT IH_ARCH_RISCV64
+#else
 #define IH_ARCH_DEFAULT IH_ARCH_RISCV
+#endif
 
 #endif	/* _U_BOOT_H_ */