ata: Add DT bindings for Faraday Technology FTIDE010

This adds device tree bindings for the Faraday Technology
FTIDE010 found in the Storlink/Storm/Cortina Systems Gemini SoC.

I am not 100% sure that this part is from Faraday Technology but
a lot points in that direction:

- A later IDE interface called FTIDE020 exist and share some
  properties.

- The SATA bridge has the same Built In Self Test (BIST) that the
  Faraday FTSATA100 seems to have, and it has version number 0100
  in the device ID register, so this is very likely a FTSATA100
  bundled with the FTIDE010.

Cc: devicetree@vger.kernel.org
Cc: John Feng-Hsin Chiang <john453@faraday-tech.com>
Cc: Greentime Hu <green.hu@gmail.com>
Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tejun Heo <tj@kernel.org>