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/arm/include/asm/arch-bcm281xx/gpio.h

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2013 Broadcom Corporation.
+ *
+ * SPDX-License-Identifier:      GPL-2.0+
+ */
+
+#ifndef __ARCH_BCM281XX_GPIO_H
+#define __ARCH_BCM281XX_GPIO_H
+
+/*
+ * Empty file - cmd_gpio.c requires this. The implementation
+ * is in drivers/gpio/kona_gpio.c instead of inlined here.
+ */
+
+#endif