Add missing UBOOT_LOADADDRESS variable.

Because we don't have the kernel class in the netmodule-fitimage recipe,
we have to add this line there.

Signed-off-by: Lucien Mueller <lucien.mueller@netmodule.com>

recipes-kernel/linux/netmodule-fitimage.bb

@@ -21,6 +21,8 @@ addtask do_deploy after assemble_fitimage_initramfs
 
 INITRAMFS_IMAGE_NAME ?= "${INITRAMFS_IMAGE}-${MACHINE}"
 
+UBOOT_LOADADDRESS ?= "${UBOOT_ENTRYPOINT}"
+
 do_configure_prepend () {
 	install -d ${S}/arch/${ARCH}/boot/
 	for DTB in ${KERNEL_DEVICETREE}; do