ARM: bcm2835: add label for uart0

This patch adds a label for uart0 to allow changing of uart0 pins.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Signed-off-by: NEric Anholt <eric@anholt.net>

arch/arm/boot/dts/bcm2835.dtsi

@@ -92,7 +92,7 @@
 			#interrupt-cells = <2>;
 		};
 
-		uart@7e201000 {
+		uart0: uart@7e201000 {
 			compatible = "brcm,bcm2835-pl011", "arm,pl011", "arm,primecell";
 			reg = <0x7e201000 0x1000>;
 			interrupts = <2 25>;