ARM: at91/dt: trivial: fix USB udc compatible string

commit 50f0a449 upstream.

To please checkpatch and the tiresome reader, add the "atmel," prefix to the
USB udc compatible string.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/atmel-usb.txt

@@ -60,9 +60,9 @@ Atmel High-Speed USB device controller
 
 Required properties:
  - compatible: Should be one of the following
-	       "at91sam9rl-udc"
-	       "at91sam9g45-udc"
-	       "sama5d3-udc"
+	       "atmel,at91sam9rl-udc"
+	       "atmel,at91sam9g45-udc"
+	       "atmel,sama5d3-udc"
  - reg: Address and length of the register set for the device
  - interrupts: Should contain usba interrupt
  - ep childnode: To specify the number of endpoints and their properties.