ARM: dts: r7s72100: add RTC_X clock inputs to device tree

Add the RTC clocks to device tree. The frequencies must be fixed values
according to the hardware manual.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r7s72100.dtsi

@@ -51,6 +51,20 @@ usb_x1_clk: usb_x1 {
 			clock-frequency = <0>;
 		};
 
+		rtc_x1_clk: rtc_x1 {
+			#clock-cells = <0>;
+			compatible = "fixed-clock";
+			/* If clk present, value must be set by board to 32678 */
+			clock-frequency = <0>;
+		};
+
+		rtc_x3_clk: rtc_x3 {
+			#clock-cells = <0>;
+			compatible = "fixed-clock";
+			/* If clk present, value must be set by board to 4000000 */
+			clock-frequency = <0>;
+		};
+
 		/* Fixed factor clocks */
 		b_clk: b {
 			#clock-cells = <0>;