arm64: dts: st: Use hyphen in node names

DTS coding style prefers hyphens instead of underscores in the node
names.  Change should be safe, because node names are not considered an
ABI.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20251223152544.155637-3-krzysztof.kozlowski@oss.qualcomm.com
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

Author: krzk

arch/arm64/boot/dts/st/stm32mp231.dtsi

@@ -776,11 +776,11 @@
 			#address-cells = <1>;
 			#size-cells = <1>;
 
-			part_number_otp@24 {
+			part-number-otp@24 {
 				reg = <0x24 0x4>;
 			};
 
-			package_otp@1e8 {
+			package-otp@1e8 {
 				reg = <0x1e8 0x1>;
 				bits = <0 3>;
 			};

arch/arm64/boot/dts/st/stm32mp251.dtsi

@@ -1765,11 +1765,11 @@
 			#address-cells = <1>;
 			#size-cells = <1>;
 
-			part_number_otp@24 {
+			part-number-otp@24 {
 				reg = <0x24 0x4>;
 			};
 
-			package_otp@1e8 {
+			package-otp@1e8 {
 				reg = <0x1e8 0x1>;
 				bits = <0 3>;
 			};