devicectree: bindings: fix location of leds common file

The leds.txt was moved and renamed. Fix references to
it accordingly.

Fixes: f6760539 ("devicetree/bindings: Move gpio-leds binding into leds directory")
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/devicetree/bindings/leds/common.txt

@@ -31,7 +31,7 @@ Optional properties for child nodes:
      "backlight" - LED will act as a back-light, controlled by the framebuffer
 		   system
      "default-on" - LED will turn on (but for leds-gpio see "default-state"
-		    property in Documentation/devicetree/bindings/gpio/led.txt)
+		    property in Documentation/devicetree/bindings/leds/leds-gpio.txt)
      "heartbeat" - LED "double" flashes at a load average based rate
      "disk-activity" - LED indicates disk activity
      "ide-disk" - LED indicates IDE disk activity (deprecated),