ARM: pxa: Use - instead of @ for DT OPP entries

Compiling the DT file with W=1, DTC warns like follows:

Warning (unit_address_vs_reg): Node /opp_table0/opp@1000000000 has a
unit name, but no reg property

Fix this by replacing '@' with '-' as the OPP nodes will never have a
"reg" property.
Reported-by: NKrzysztof Kozlowski <krzk@kernel.org>
Reported-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Suggested-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRobert Jarzmik <robert.jarzmik@free.fr>

arch/arm/boot/dts/pxa25x.dtsi

@@ -93,22 +93,22 @@
 	pxa250_opp_table: opp_table0 {
 		compatible = "operating-points-v2";
 
-		opp@99532800 {
+		opp-99532800 {
 			opp-hz = /bits/ 64 <99532800>;
 			opp-microvolt = <1000000 950000 1650000>;
 			clock-latency-ns = <20>;
 		};
-		opp@199065600 {
+		opp-199065600 {
 			opp-hz = /bits/ 64 <199065600>;
 			opp-microvolt = <1000000 950000 1650000>;
 			clock-latency-ns = <20>;
 		};
-		opp@298598400 {
+		opp-298598400 {
 			opp-hz = /bits/ 64 <298598400>;
 			opp-microvolt = <1100000 1045000 1650000>;
 			clock-latency-ns = <20>;
 		};
-		opp@398131200 {
+		opp-398131200 {
 			opp-hz = /bits/ 64 <398131200>;
 			opp-microvolt = <1300000 1235000 1650000>;
 			clock-latency-ns = <20>;

arch/arm/boot/dts/pxa27x.dtsi

@@ -141,37 +141,37 @@
 	pxa270_opp_table: opp_table0 {
 		compatible = "operating-points-v2";
 
-		opp@104000000 {
+		opp-104000000 {
 			opp-hz = /bits/ 64 <104000000>;
 			opp-microvolt = <900000 900000 1705000>;
 			clock-latency-ns = <20>;
 		};
-		opp@156000000 {
+		opp-156000000 {
 			opp-hz = /bits/ 64 <156000000>;
 			opp-microvolt = <1000000 1000000 1705000>;
 			clock-latency-ns = <20>;
 		};
-		opp@208000000 {
+		opp-208000000 {
 			opp-hz = /bits/ 64 <208000000>;
 			opp-microvolt = <1180000 1180000 1705000>;
 			clock-latency-ns = <20>;
 		};
-		opp@312000000 {
+		opp-312000000 {
 			opp-hz = /bits/ 64 <312000000>;
 			opp-microvolt = <1250000 1250000 1705000>;
 			clock-latency-ns = <20>;
 		};
-		opp@416000000 {
+		opp-416000000 {
 			opp-hz = /bits/ 64 <416000000>;
 			opp-microvolt = <1350000 1350000 1705000>;
 			clock-latency-ns = <20>;
 		};
-		opp@520000000 {
+		opp-520000000 {
 			opp-hz = /bits/ 64 <520000000>;
 			opp-microvolt = <1450000 1450000 1705000>;
 			clock-latency-ns = <20>;
 		};
-		opp@624000000 {
+		opp-624000000 {
 			opp-hz = /bits/ 64 <624000000>;
 			opp-microvolt = <1550000 1550000 1705000>;
 			clock-latency-ns = <20>;