boards: stm32: stm32n6570_dk: Comment out nvmem properties in DTS file

Commented out the nvmem properties in the DTS file
to avoid confusion for n6 boards that do not have
the OTP MAC address programmed.

Signed-off-by: Julien Racki <julien.racki-ext@st.com>

Author: juickar

boards/st/stm32n6570_dk/stm32n6570_dk_common.dtsi

@@ -489,8 +489,9 @@ zephyr_udc0: &usbotg_hs1 {
 	pinctrl-names = "default";
 	phy-connection-type = "rgmii";
 	phy-handle = <&eth_phy>;
-	nvmem-cells = <&mac_address0>;
-	nvmem-cell-names = "mac-address";
+	/* These properties can be enabled, but OTP MAC may be unprogrammed. */
+	/* nvmem-cells = <&mac_address0>; */
+	/* nvmem-cell-names = "mac-address"; */
 };
 
 &mdio {