arm64: dts: rockchip: align rk3399 DMC OPP table with bindings

Bindings expect certain pattern for OPP table node name and underscores
are not allowed:

  rk3399-rock-pi-4a-plus.dtb: dmc_opp_table: $nodename:0: 'dmc_opp_table' does not match '^opp-table(-[a-z0-9]+)?$'
Signed-off-by: NKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230119124631.91080-1-krzysztof.kozlowski@linaro.orgSigned-off-by: NHeiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399-op1-opp.dtsi

@@ -111,7 +111,7 @@
 		};
 	};
 
-	dmc_opp_table: dmc_opp_table {
+	dmc_opp_table: opp-table-3 {
 		compatible = "operating-points-v2";
 
 		opp00 {