arm64: dts: zynqmp: Fix node names which contain "_"

s/_/-/ for node names.

It fixes warnings like this:
... Warning (node_name_chars_strict): /cpu_opp_table:
Character '_' not recommended in node name ...

Issues reported by make dtbs W=12

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/dts/zynqmp-clk.dtsi b/arch/arm/dts/zynqmp-clk.dtsi
index 9ef55ad..c9464ec 100644
--- a/arch/arm/dts/zynqmp-clk.dtsi
+++ b/arch/arm/dts/zynqmp-clk.dtsi
@@ -61,13 +61,13 @@
 		clock-accuracy = <100>;
 	};
 
-	dpdma_clk: dpdma_clk {
+	dpdma_clk: dpdma-clk {
 		compatible = "fixed-clock";
 		#clock-cells = <0x0>;
 		clock-frequency = <533000000>;
 	};
 
-	drm_clock: drm_clock {
+	drm_clock: drm-clock {
 		compatible = "fixed-clock";
 		#clock-cells = <0x0>;
 		clock-frequency = <262750000>;