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-zcu102-revA.dts b/arch/arm/dts/zynqmp-zcu102-revA.dts
index 78110c4..7d2f59b 100644
--- a/arch/arm/dts/zynqmp-zcu102-revA.dts
+++ b/arch/arm/dts/zynqmp-zcu102-revA.dts
@@ -58,7 +58,7 @@
 
 	leds {
 		compatible = "gpio-leds";
-		heartbeat_led {
+		heartbeat-led {
 			label = "heartbeat";
 			gpios = <&gpio 23 GPIO_ACTIVE_HIGH>;
 			linux,default-trigger = "heartbeat";
@@ -213,25 +213,25 @@
 		gpio-line-names = "PS_GTR_LAN_SEL0", "PS_GTR_LAN_SEL1", "PS_GTR_LAN_SEL2", "PS_GTR_LAN_SEL3",
 				"PCI_CLK_DIR_SEL", "IIC_MUX_RESET_B", "GEM3_EXP_RESET_B",
 				"", "", "", "", "", "", "", "", "";
-		gtr_sel0 {
+		gtr-sel0 {
 			gpio-hog;
 			gpios = <0 0>;
 			output-low; /* PCIE = 0, DP = 1 */
 			line-name = "sel0";
 		};
-		gtr_sel1 {
+		gtr-sel1 {
 			gpio-hog;
 			gpios = <1 0>;
 			output-high; /* PCIE = 0, DP = 1 */
 			line-name = "sel1";
 		};
-		gtr_sel2 {
+		gtr-sel2 {
 			gpio-hog;
 			gpios = <2 0>;
 			output-high; /* PCIE = 0, USB0 = 1 */
 			line-name = "sel2";
 		};
-		gtr_sel3 {
+		gtr-sel3 {
 			gpio-hog;
 			gpios = <3 0>;
 			output-high; /* PCIE = 0, SATA = 1 */