ARM: dts: at91: add labels to soc dtsi for derivative boards

This adds labels to commonly used device-tree nodes so that derivative
boards can avoid ahb/apb hierarchy.

Signed-off-by: Ben Whitten <[e-mail]>
Signed-off-by: Alexandre Belloni <[e-mail]>

arch/arm/boot/dts/at91sam9x5.dtsi

···
 				};
 			};
 
-			rstc@fffffe00 {
+			reset_controller: rstc@fffffe00 {
 				compatible = "atmel,at91sam9g45-rstc";
 				reg = <0xfffffe00 0x10>;
 				clocks = <&clk32k>;
 			};
 
-			shdwc@fffffe10 {
+			shutdown_controller: shdwc@fffffe10 {
 				compatible = "atmel,at91sam9x5-shdwc";
 				reg = <0xfffffe10 0x10>;
 				clocks = <&clk32k>;
···
 				clock-names = "dma_clk";
 			};
 
-			pinctrl@fffff400 {
+			pinctrl: pinctrl@fffff400 {
 				#address-cells = <1>;
 				#size-cells = <1>;
 				compatible = "atmel,at91sam9x5-pinctrl", "atmel,at91rm9200-pinctrl", "simple-bus";
···
 				};
 			};
 
-			watchdog@fffffe40 {
+			watchdog: watchdog@fffffe40 {
 				compatible = "atmel,at91sam9260-wdt";
 				reg = <0xfffffe40 0x10>;
 				interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;

arch/arm/boot/dts/sama5d3.dtsi

···
 				atmel,external-irqs = <47>;
 			};
 
-			pinctrl@fffff200 {
+			pinctrl: pinctrl@fffff200 {
 				#address-cells = <1>;
 				#size-cells = <1>;
 				compatible = "atmel,sama5d3-pinctrl", "atmel,at91sam9x5-pinctrl", "simple-bus";
···
 				};
 			};
 
-			rstc@fffffe00 {
+			reset_controller: rstc@fffffe00 {
 				compatible = "atmel,sama5d3-rstc", "atmel,at91sam9g45-rstc";
 				reg = <0xfffffe00 0x10>;
 				clocks = <&clk32k>;
 			};
 
-			shutdown-controller@fffffe10 {
+			shutdown_controller: shutdown-controller@fffffe10 {
 				compatible = "atmel,at91sam9x5-shdwc";
 				reg = <0xfffffe10 0x10>;
 				clocks = <&clk32k>;
···
 				clocks = <&mck>;
 			};
 
-			watchdog@fffffe40 {
+			watchdog: watchdog@fffffe40 {
 				compatible = "atmel,at91sam9260-wdt";
 				reg = <0xfffffe40 0x10>;
 				interrupts = <4 IRQ_TYPE_LEVEL_HIGH 7>;