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/sh/cpu/sh2/config.mk

@@ -0,0 +1,17 @@
+#
+# (C) Copyright 2007-2008
+# Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+#
+ENDIANNESS += -EB
+
+ifdef CONFIG_CPU_SH2A
+PLATFORM_CPPFLAGS += -m2a -m2a-nofpu -mb
+else # SH2
+PLATFORM_CPPFLAGS += -m3e -mb
+endif
+PLATFORM_CPPFLAGS += $(call cc-option,-mno-fdpic)
+
+PLATFORM_LDFLAGS += $(ENDIANNESS)