arm64: dts: allwinner: h6: Use - instead of @ for DT OPP entries

DTC and the dt-validate tools report warnings for opp with the format
opp@$frequency: dtc for a missing reg property, and dt-validate since
the binding requires child nodes to have the format opp-$frequency.

Change this to the latter format.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://lore.kernel.org/r/20210114113538.1233933-16-maxime@cerno.tech

arch/arm64/boot/dts/allwinner/sun50i-h6-cpu-opp.dtsi

@@ -8,7 +8,7 @@ cpu_opp_table: cpu-opp-table {
 		nvmem-cells = <&cpu_speed_grade>;
 		opp-shared;
 
-		opp@480000000 {
+		opp-480000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <480000000>;
 
@@ -17,7 +17,7 @@ opp@480000000 {
 			opp-microvolt-speed2 = <820000 820000 1200000>;
 		};
 
-		opp@720000000 {
+		opp-720000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <720000000>;
 
@@ -26,7 +26,7 @@ opp@720000000 {
 			opp-microvolt-speed2 = <820000 820000 1200000>;
 		};
 
-		opp@816000000 {
+		opp-816000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <816000000>;
 
@@ -35,7 +35,7 @@ opp@816000000 {
 			opp-microvolt-speed2 = <820000 820000 1200000>;
 		};
 
-		opp@888000000 {
+		opp-888000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <888000000>;
 
@@ -44,7 +44,7 @@ opp@888000000 {
 			opp-microvolt-speed2 = <820000 820000 1200000>;
 		};
 
-		opp@1080000000 {
+		opp-1080000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <1080000000>;
 
@@ -53,7 +53,7 @@ opp@1080000000 {
 			opp-microvolt-speed2 = <880000 880000 1200000>;
 		};
 
-		opp@1320000000 {
+		opp-1320000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <1320000000>;
 
@@ -62,7 +62,7 @@ opp@1320000000 {
 			opp-microvolt-speed2 = <940000 940000 1200000>;
 		};
 
-		opp@1488000000 {
+		opp-1488000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <1488000000>;
 
@@ -71,7 +71,7 @@ opp@1488000000 {
 			opp-microvolt-speed2 = <1000000 1000000 1200000>;
 		};
 
-		opp@1608000000 {
+		opp-1608000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <1608000000>;
 
@@ -80,7 +80,7 @@ opp@1608000000 {
 			opp-microvolt-speed2 = <1030000 1030000 1200000>;
 		};
 
-		opp@1704000000 {
+		opp-1704000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <1704000000>;
 
@@ -89,7 +89,7 @@ opp@1704000000 {
 			opp-microvolt-speed2 = <1060000 1060000 1200000>;
 		};
 
-		opp@1800000000 {
+		opp-1800000000 {
 			clock-latency-ns = <244144>; /* 8 32k periods */
 			opp-hz = /bits/ 64 <1800000000>;