clocksource: Augment bindings for Faraday timer

It turns out that the Cortina Gemini timer block is just a
standard IP block from Faraday Technology named FTTMR010.

In order to make things clear and understandable, we rename the
bindings with a Faraday compatible as primary and the Cortina
gemini as a more specific case.

For the plain Faraday timer we require two clock references,
while the Gemini can keep it's syscon lookup pattern.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/timer/cortina,gemini-timer.txt

-Cortina Systems Gemini timer
-
-This timer is embedded in the Cortina Systems Gemini SoCs.
-
-Required properties:
-
-- compatible : Must be "cortina,gemini-timer"
-- reg : Should contain registers location and length
-- interrupts : Should contain the three timer interrupts with
-  flags for rising edge
-- syscon : a phandle to the global Gemini system controller
-
-Example:
-
-timer@43000000 {
-	compatible = "cortina,gemini-timer";
-	reg = <0x43000000 0x1000>;
-	interrupts = <14 IRQ_TYPE_EDGE_RISING>, /* Timer 1 */
-		   <15 IRQ_TYPE_EDGE_RISING>, /* Timer 2 */
-		   <16 IRQ_TYPE_EDGE_RISING>; /* Timer 3 */
-	syscon = <&syscon>;
-};

Documentation/devicetree/bindings/timer/faraday,fttmr010.txt

+Faraday Technology timer
+
+This timer is a generic IP block from Faraday Technology, embedded in the
+Cortina Systems Gemini SoCs and other designs.
+
+Required properties:
+
+- compatible : Must be one of
+  "faraday,fttmr010"
+  "cortina,gemini-timer"
+- reg : Should contain registers location and length
+- interrupts : Should contain the three timer interrupts usually with
+  flags for falling edge
+
+Optionally required properties:
+
+- clocks : a clock to provide the tick rate for "faraday,fttmr010"
+- clock-names : should be "EXTCLK" and "PCLK" for the external tick timer
+  and peripheral clock respectively, for "faraday,fttmr010"
+- syscon : a phandle to the global Gemini system controller if the compatible
+  type is "cortina,gemini-timer"
+
+Example:
+
+timer@43000000 {
+	compatible = "faraday,fttmr010";
+	reg = <0x43000000 0x1000>;
+	interrupts = <14 IRQ_TYPE_EDGE_FALLING>, /* Timer 1 */
+		   <15 IRQ_TYPE_EDGE_FALLING>, /* Timer 2 */
+		   <16 IRQ_TYPE_EDGE_FALLING>; /* Timer 3 */
+	clocks = <&extclk>, <&pclk>;
+	clock-names = "EXTCLK", "PCLK";
+};