ARM: dts: add a devicetree for Teltonika RUT1xx

This devicetree is simply based on the board file in
arch/arm/mach-gemini/board-rut1xx.c and contain the
equivalent platform data, mainly just moving the GPIOs
from the global numberspace to explicitly reference their
parent GPIO.

Cc: Janos Laube <janos.dev@gmail.com>
Cc: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Cc: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>