DT: leds: Add flash LED devices related properties

Addition of a LED Flash class extension entails the need for flash LED
specific device tree properties. The properties being added are:
max-microamp, flash-max-microamp, flash-timeout-microsec.

(cooloney@gmail.com: remove white spaces)
Signed-off-by: NPavel Machek <pavel@ucw.cz>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: NJacek Anaszewski <j.anaszewski@samsung.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NBryan Wu <cooloney@gmail.com>

Documentation/devicetree/bindings/leds/common.txt

@@ -14,6 +14,15 @@ Optional properties for child nodes:
      "ide-disk" - LED indicates disk activity
      "timer" - LED flashes at a fixed, configurable rate
 
+- max-microamp : maximum intensity in microamperes of the LED
+		 (torch LED for flash devices)
+- flash-max-microamp : maximum intensity in microamperes of the
+                       flash LED; it is mandatory if the LED should
+		       support the flash mode
+- flash-timeout-us : timeout in microseconds after which the flash
+                     LED is turned off
+
+
 Examples:
 
 system-status {
@@ -21,3 +30,10 @@ system-status {
 	linux,default-trigger = "heartbeat";
 	...
 };
+
+camera-flash {
+	label = "Flash";
+	max-microamp = <50000>;
+	flash-max-microamp = <320000>;
+	flash-timeout-us = <500000>;
+}