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/board/spear/common/Makefile

@@ -0,0 +1,14 @@
+#
+# (C) Copyright 2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+ifdef CONFIG_SPL_BUILD
+# necessary to create built-in.o
+obj- := __dummy__.o
+else
+obj-y	:= spr_misc.o
+obj-y	+= spr_lowlevel_init.o
+endif