ARM: at91/dt: at91sam9263: use slow clock where necessary

The watchdog, the reset controller, the two real-time timers, the shutdown
controller and the timer counter need the slow clock, add it where
necessary.
Acked-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

arch/arm/boot/dts/at91sam9263.dtsi

@@ -377,18 +377,20 @@
 				compatible = "atmel,at91rm9200-tcb";
 				reg = <0xfff7c000 0x100>;
 				interrupts = <19 IRQ_TYPE_LEVEL_HIGH 0>;
-				clocks = <&tcb_clk>;
-				clock-names = "t0_clk";
+				clocks = <&tcb_clk>, <&slow_xtal>;
+				clock-names = "t0_clk", "slow_clk";
 			};
 
 			rstc@fffffd00 {
 				compatible = "atmel,at91sam9260-rstc";
 				reg = <0xfffffd00 0x10>;
+				clocks = <&slow_xtal>;
 			};
 
 			shdwc@fffffd10 {
 				compatible = "atmel,at91sam9260-shdwc";
 				reg = <0xfffffd10 0x10>;
+				clocks = <&slow_xtal>;
 			};
 
 			pinctrl@fffff200 {
@@ -902,6 +904,7 @@
 				compatible = "atmel,at91sam9260-wdt";
 				reg = <0xfffffd40 0x10>;
 				interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;
+				clocks = <&slow_xtal>;
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;