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>

Documentation/devicetree/bindings/ata/faraday,ftide010.txt

+* Faraday Technology FTIDE010 PATA controller
+
+This controller is the first Faraday IDE interface block, used in the
+StorLink SL2312 and SL3516, later known as the Cortina Systems Gemini
+platform. The controller can do PIO modes 0 through 4, Multi-word DMA
+(MWDM)modes 0 through 2 and Ultra DMA modes 0 through 6.
+
+On the Gemini platform, this PATA block is accompanied by a PATA to
+SATA bridge in order to support SATA. This is why a phandle to that
+controller is compulsory on that platform.
+
+The timing properties are unique per-SoC, not per-board.
+
+Required properties:
+- compatible: should be one of
+  "cortina,gemini-pata", "faraday,ftide010"
+  "faraday,ftide010"
+- interrupts: interrupt for the block
+- reg: registers and size for the block
+
+Optional properties:
+- clocks: a SoC clock running the peripheral.
+- clock-names: should be set to "PCLK" for the peripheral clock.
+
+Required properties for "cortina,gemini-pata" compatible:
+- sata: a phande to the Gemini PATA to SATA bridge, see
+  cortina,gemini-sata-bridge.txt for details.
+
+Example:
+
+ata@63000000 {
+	compatible = "cortina,gemini-pata", "faraday,ftide010";
+	reg = <0x63000000 0x100>;
+	interrupts = <4 IRQ_TYPE_EDGE_RISING>;
+	clocks = <&gcc GEMINI_CLK_GATE_IDE>;
+	clock-names = "PCLK";
+	sata = <&sata>;
+};