x15: pinmux change, using ti's u-boot fork going forward...

So as u-boot is now taking care of the default pinmuxing, we need to
upgrade any images pre "march 8th 2015" (next sunday)...

First: u-boot:

cd /opt/scripts/tools/developers/
git pull
sudo ./update_bootloader.sh

This will pull in:

http://git.ti.com/gitweb/?p=ti-u-boot/ti-u-boot.git;a=shortlog;h=refs/heads/ti-u-boot-2014.07