arm64: dts: imx8mm: Add opp-suspend property to OPP table

Add opp-suspend property to each OPP, the of opp core will
select the OPP HW supported and with highest rate to be
suspend opp, it will speed up the suspend/resume process.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mm.dtsi

@@ -104,6 +104,7 @@ opp-1200000000 {
 			opp-microvolt = <850000>;
 			opp-supported-hw = <0xe>, <0x7>;
 			clock-latency-ns = <150000>;
+			opp-suspend;
 		};
 
 		opp-1600000000 {
@@ -111,6 +112,7 @@ opp-1600000000 {
 			opp-microvolt = <900000>;
 			opp-supported-hw = <0xc>, <0x7>;
 			clock-latency-ns = <150000>;
+			opp-suspend;
 		};
 
 		opp-1800000000 {
@@ -118,6 +120,7 @@ opp-1800000000 {
 			opp-microvolt = <1000000>;
 			opp-supported-hw = <0x8>, <0x3>;
 			clock-latency-ns = <150000>;
+			opp-suspend;
 		};
 	};