U-Boot loader for Banana Pi M2.

To install this bootloader, follow the instructions in
 http://linux-sunxi.org/Bootable_SD_card#Bootloader

This version is patched so that:
 * ELF and API features are enabled.
 * The default environment is trimmed to just what's needed to boot.
 * The saveenv command writes to the file u-boot.env on the FAT partition.
 * The DTB file name is chosen based on the board model and passed to ubldr
   using the fdtfile env variable.  ubldr loads the DTB from /boot/dtb/ on
   the FreeBSD partition.
 * By default, it loads PIE ubldr.bin from file ubldr.bin on the FAT partition
   to address 0x42000000, and launches it.

For information about running FreeBSD on Banana Pi, see
 https://wiki.freebsd.org/FreeBSD/arm/Allwinner

For general information about U-Boot see WWW: http://www.denx.de/wiki/U-Boot