ARM: dts: Add the FOTG210 USB host to Gemini boards

This adds the FOTG210 USB host controller to the Gemini
device trees. In the main SoC DTSI it is flagged as disabled
and then it is selectively enabled on the devices that utilize
it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>