avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/sparc/cpu/leon3/Makefile

@@ -0,0 +1,10 @@
+#
+# (C) Copyright 2003-2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+extra-y	= start.o
+obj-y	= cpu_init.o serial.o cpu.o ambapp.o ambapp_low.o ambapp_low_c.o \
+	interrupts.o prom.o usb_uhci.o memcfg.o memcfg_low.o