Use net.HardwareAddr for FDBasedLink.LinkAddress

It prints formatted to the log.

PiperOrigin-RevId: 252699551

runsc/boot/network.go

@@ -56,7 +56,7 @@ type FDBasedLink struct {
 	Addresses   []net.IP
 	Routes      []Route
 	GSOMaxSize  uint32
-	LinkAddress []byte
+	LinkAddress net.HardwareAddr
 
 	// NumChannels controls how many underlying FD's are to be used to
 	// create this endpoint.

runsc/sandbox/network.go

@@ -228,7 +228,7 @@ func createInterfacesAndRoutesFromNS(conn *urpc.Client, nsPath string, enableGSO
 		if err != nil {
 			return fmt.Errorf("getting link for interface %q: %v", iface.Name, err)
 		}
-		link.LinkAddress = []byte(ifaceLink.Attrs().HardwareAddr)
+		link.LinkAddress = ifaceLink.Attrs().HardwareAddr
 
 		log.Debugf("Setting up network channels")
 		// Create the socket for the device.