ARM: tegra: colibri_t20: iris: annotate uarts

Annotate UART-A and UART-B.
Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra20-colibri-iris.dts

@@ -98,10 +98,12 @@ usbh-pen {
 		};
 	};
 
+	/* Colibri UART-A */
 	serial@70006000 {
 		status = "okay";
 	};
 
+	/* Colibri UART-B */
 	serial@70006300 {
 		status = "okay";
 	};