ARM: dts: imx7d: Add opp-suspend property

Add "opp-suspend" property for i.MX7D to make sure system
suspend with max available opp.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Leonard Crestez <leonard.crestez@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx7d.dtsi

@@ -44,6 +44,7 @@ opp-792000000 {
 			opp-microvolt = <1000000>;
 			clock-latency-ns = <150000>;
 			opp-supported-hw = <0xd>, <0xf>;
+			opp-suspend;
 		};
 
 		opp-996000000 {
@@ -51,6 +52,7 @@ opp-996000000 {
 			opp-microvolt = <1100000>;
 			clock-latency-ns = <150000>;
 			opp-supported-hw = <0xc>, <0xf>;
+			opp-suspend;
 		};
 
 		opp-1200000000 {
@@ -58,6 +60,7 @@ opp-1200000000 {
 			opp-microvolt = <1225000>;
 			clock-latency-ns = <150000>;
 			opp-supported-hw = <0x8>, <0xf>;
+			opp-suspend;
 		};
 	};