dt-bindings: Clean-up OPP binding node names in examples

In preparation to convert OPP bindings to DT schema, clean-up a few OPP
binding node names in the binding examples.

Cc: Georgi Djakov <djakov@kernel.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Leonard Crestez <leonard.crestez@nxp.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRob Herring <robh@kernel.org>
Acked-by: NGeorgi Djakov <djakov@kernel.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>

Documentation/devicetree/bindings/gpu/arm,mali-bifrost.yaml

@@ -136,7 +136,7 @@ examples:
       resets = <&reset 0>, <&reset 1>;
     };
 
-    gpu_opp_table: opp_table0 {
+    gpu_opp_table: opp-table {
       compatible = "operating-points-v2";
 
       opp-533000000 {

Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml

@@ -160,7 +160,7 @@ examples:
       #cooling-cells = <2>;
     };
 
-    gpu_opp_table: opp_table0 {
+    gpu_opp_table: opp-table {
       compatible = "operating-points-v2";
 
       opp-533000000 {

Documentation/devicetree/bindings/interconnect/fsl,imx8m-noc.yaml

@@ -81,10 +81,10 @@ examples:
         noc_opp_table: opp-table {
             compatible = "operating-points-v2";
 
-            opp-133M {
+            opp-133333333 {
                 opp-hz = /bits/ 64 <133333333>;
             };
-            opp-800M {
+            opp-800000000 {
                 opp-hz = /bits/ 64 <800000000>;
             };
         };