Add the Linaro GNU 5.1 Binary Toolchain Add the Linaro GNU Binary Toolchain as a third party prebuilt. This is needed for the aarch64 cross compiler (gcc), to facilitate CI testing. Signed-off-by: Fuad Tabba <tabba@google.com> Change-Id: I2c39123a68172e71bbdcc559c03a614ec828e97c