tools: mkimage: add support for Vybrid image format

This format can be flashed directly at address 0 of
the NAND FLASH, as it contains all necessary headers.

Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud@3adev.fr>
diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 8f85862..542b897 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -144,4 +144,7 @@
 ALL-y += u-boot.imx
 endif
 endif
+ifneq ($(CONFIG_VF610),)
+ALL-y += u-boot.vyb
+endif
 endif