net: cdc-phonet: Staticize usbpn_probe

'usbpn_probe' is referenced only in this file. Make it static.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Acked-by: Rémi Denis-Courmont <remi@remlab.net>
Cc: Rémi Denis-Courmont <remi@remlab.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/cdc-phonet.c

@@ -328,7 +328,7 @@ MODULE_DEVICE_TABLE(usb, usbpn_ids);
 
 static struct usb_driver usbpn_driver;
 
-int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
+static int usbpn_probe(struct usb_interface *intf, const struct usb_device_id *id)
 {
 	static const char ifname[] = "usbpn%d";
 	const struct usb_cdc_union_desc *union_header = NULL;