ARM: at91/dt: at91rm9200: use slow clock where necessary

The system timer, the RTC and the timer counters need the slow clock, add
it.
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

arch/arm/boot/dts/at91rm9200.dtsi

@@ -359,6 +359,7 @@ st: timer@fffffd00 {
 				compatible = "atmel,at91rm9200-st", "syscon", "simple-mfd";
 				reg = <0xfffffd00 0x100>;
 				interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;
+				clocks = <&slow_xtal>;
 
 				watchdog {
 					compatible = "atmel,at91rm9200-wdt";
@@ -369,6 +370,7 @@ rtc: rtc@fffffe00 {
 				compatible = "atmel,at91rm9200-rtc";
 				reg = <0xfffffe00 0x40>;
 				interrupts = <1 IRQ_TYPE_LEVEL_HIGH 7>;
+				clocks = <&slow_xtal>;
 				status = "disabled";
 			};
 
@@ -378,8 +380,8 @@ tcb0: timer@fffa0000 {
 				interrupts = <17 IRQ_TYPE_LEVEL_HIGH 0
 					      18 IRQ_TYPE_LEVEL_HIGH 0
 					      19 IRQ_TYPE_LEVEL_HIGH 0>;
-				clocks = <&tc0_clk>, <&tc1_clk>, <&tc2_clk>;
-				clock-names = "t0_clk", "t1_clk", "t2_clk";
+				clocks = <&tc0_clk>, <&tc1_clk>, <&tc2_clk>, <&slow_xtal>;
+				clock-names = "t0_clk", "t1_clk", "t2_clk", "slow_clk";
 			};
 
 			tcb1: timer@fffa4000 {
@@ -388,8 +390,8 @@ tcb1: timer@fffa4000 {
 				interrupts = <20 IRQ_TYPE_LEVEL_HIGH 0
 					      21 IRQ_TYPE_LEVEL_HIGH 0
 					      22 IRQ_TYPE_LEVEL_HIGH 0>;
-				clocks = <&tc3_clk>, <&tc4_clk>, <&tc5_clk>;
-				clock-names = "t0_clk", "t1_clk", "t2_clk";
+				clocks = <&tc3_clk>, <&tc4_clk>, <&tc5_clk>, <&slow_xtal>;
+				clock-names = "t0_clk", "t1_clk", "t2_clk", "slow_clk";
 			};
 
 			i2c0: i2c@fffb8000 {