ARM: dts: imx7s: add snvs rtc clock

Add i.MX7 SNVS RTC clock.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Acked-by: Dong Aisheng <aisheng.dong@nxp.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Documentation/devicetree/bindings/crypto/fsl-sec4.txt

@@ -415,12 +415,27 @@ Secure Non-Volatile Storage (SNVS) Low Power (LP) RTC Node
 	value type: <u32>
 	Definition: LP register offset. default it is 0x34.
 
+   - clocks
+      Usage: optional, required if SNVS LP RTC requires explicit
+          enablement of clocks
+      Value type: <prop_encoded-array>
+      Definition:  a clock specifier describing the clock required for
+          enabling and disabling SNVS LP RTC.
+
+   - clock-names
+      Usage: optional, required if SNVS LP RTC requires explicit
+          enablement of clocks
+      Value type: <string>
+      Definition: clock name string should be "snvs-rtc".
+
 EXAMPLE
 	sec_mon_rtc_lp@1 {
 		compatible = "fsl,sec-v4.0-mon-rtc-lp";
 		interrupts = <93 2>;
 		regmap = <&snvs>;
 		offset = <0x34>;
+		clocks = <&clks IMX7D_SNVS_CLK>;
+		clock-names = "snvs-rtc";
 	};
 
 =====================================================================
@@ -543,6 +558,8 @@ FULL EXAMPLE
 			regmap = <&sec_mon>;
 			offset = <0x34>;
 			interrupts = <93 2>;
+			clocks = <&clks IMX7D_SNVS_CLK>;
+			clock-names = "snvs-rtc";
 		};
 
 		snvs-pwrkey@020cc000 {

arch/arm/boot/dts/imx7s.dtsi

@@ -551,6 +551,8 @@ snvs_rtc: snvs-rtc-lp {
 					offset = <0x34>;
 					interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>,
 						     <GIC_SPI 20 IRQ_TYPE_LEVEL_HIGH>;
+					clocks = <&clks IMX7D_SNVS_CLK>;
+					clock-names = "snvs-rtc";
 				};
 
 				snvs_poweroff: snvs-poweroff {