arm64: dts: qcom: qcs404: add sleep clk fixed rate oscillator

This fixed rate clock is required for the operation of some devices
(ie watchdog).
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

arch/arm64/boot/dts/qcom/qcs404.dtsi

@@ -22,6 +22,12 @@ xo_board: xo-board {
 			#clock-cells = <0>;
 			clock-frequency = <19200000>;
 		};
+
+		sleep_clk: sleep-clk {
+			compatible = "fixed-clock";
+			#clock-cells = <0>;
+			clock-frequency = <32768>;
+		};
 	};
 
 	cpus {