Tegra tools git repo relocation

Certain Tegra-related tools have moved location from NVIDIA servers to github.

The intent is to allow these tools to be more than just a git repo; we could start posting release tarballs, or using the github wikis or issue tracker.

The old and new URLs are:

git://nv-tegra.nvidia.com/tools/cbootimage.git
git://github.com/NVIDIA/cbootimage.git

git://nv-tegra.nvidia.com/tools/tegra-cbootimage-configs.git
git://github.com/NVIDIA/cbootimage-configs.git
(Note the repo rename there too)

git://nv-tegra.nvidia.com/tools/tegrarcm.git
git://github.com/NVIDIA/tegrarcm.git