drivers: mdio: nxp_enet: Fix "expected statement" clangsa error

clangsa reports the error

mdio_nxp_enet.c:245:10: error: label at end of compound statement:
expected statement

Signed-off-by: Pieter De Gendt <pieter.degendt@basalte.be>

drivers/mdio/mdio_nxp_enet.c

@@ -243,6 +243,7 @@ void nxp_enet_mdio_callback(const struct device *dev,
 		data->interrupt_up = true;
 		break;
 	default:
+		break;
 	}
 }