meta-google: google-usb-network: Allow specifying interface name

Change-Id: Icdf1b12993b96d13008ddae93a54aa5bd6b35173
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/recipes-google/networking/google-usb-network/usb_network.service.m4 b/meta-google/recipes-google/networking/google-usb-network/usb_network.service.m4
index cefaff9..252f409 100644
--- a/meta-google/recipes-google/networking/google-usb-network/usb_network.service.m4
+++ b/meta-google/recipes-google/networking/google-usb-network/usb_network.service.m4
@@ -21,7 +21,7 @@
     --dev-type "M_BMC_USB_TYPE" \
     HOST_MAC_ARG(M_BMC_USB_HOST_MAC) \
     DEV_MAC_ARG(M_BMC_USB_DEV_MAC) \
-    --iface-name usb0 \
+    --iface-name "M_BMC_USB_IFACE" \
     --bind-device "M_BMC_USB_BIND_DEV"
 ExecStop=M_SCRIPT_INSTALL_DIR/usb_network.sh stop