MIPS: BMIPS: Add DTS files for several platforms

MIPS: BMIPS: Add DTS files for several platforms

Most of the supported chips use legacy (non-DT) bootloaders, so they will
need to select an appropriate builtin DTB at compile time until the
bootloader is updated.  Provide suitable DTS files, and a means to compile
one of them into the kernel image.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Cc: f.fainelli@gmail.com
Cc: abrestic@chromium.org
Cc: tglx@linutronix.de
Cc: jason@lakedaemon.net
Cc: jogo@openwrt.org
Cc: arnd@arndb.de
Cc: computersforpeace@gmail.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8858/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>