clocksource: armada-370-xp: Fix device-tree binding

This commit fixes the DT binding for the Armada 370/XP SoC timer.
The previous "marvell,armada-370-xp-timer" compatible is removed and
two new compatible strings are introduced: "marvell,armada-xp-timer"
and "marvell,armada-370-timer".

The rationale behind this change is that the Armada 370 SoC and the
Armada XP SoC timers are not really compatible:

  * Armada 370 has no 25 MHz fixed timer.

  * Armada XP cannot work properly without such 25 MHz fixed timer
    as doing otherwise leads to using a clocksource whose frequency
    varies when doing cpufreq frequency changes.

This commit also removes the "marvell,timer-25Mhz" property, given
it's now meaningless.

Cc: devicetree@vger.kernel.org
Acked-by: NJason Cooper <jason@lakedaemon.net>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>

Documentation/devicetree/bindings/timer/marvell,armada-370-xp-timer.txt

@@ -2,14 +2,31 @@ Marvell Armada 370 and Armada XP Timers
 ---------------------------------------
 
 Required properties:
-- compatible: Should be "marvell,armada-370-xp-timer"
+- compatible: Should be either "marvell,armada-370-timer" or
+  "marvell,armada-xp-timer" as appropriate.
 - interrupts: Should contain the list of Global Timer interrupts and
   then local timer interrupts
 - reg: Should contain location and length for timers register. First
   pair for the Global Timer registers, second pair for the
   local/private timers.
-- clocks: clock driving the timer hardware
+- clocks: clock driving the timer hardware, only required for
+  "marvell,armada-370-timer";
 
-Optional properties:
-- marvell,timer-25Mhz: Tells whether the Global timer supports the 25
-  Mhz fixed mode (available on Armada XP and not on Armada 370)
+Examples:
+
+- Armada 370:
+
+	timer {
+		compatible = "marvell,armada-370-timer";
+		reg = <0x20300 0x30>, <0x21040 0x30>;
+		interrupts = <37>, <38>, <39>, <40>, <5>, <6>;
+		clocks = <&coreclk 2>;
+	};
+
+- Armada XP:
+
+	timer {
+		compatible = "marvell,armada-xp-timer";
+		reg = <0x20300 0x30>, <0x21040 0x30>;
+		interrupts = <37>, <38>, <39>, <40>, <5>, <6>;
+	};