usb ethernet gadget: split RNDIS function

This is a RNDIS function driver, extracted from the all-in-one
Ethernet gadget driver.

Lightly tested ... there seems to be a pre-existing problem when
talking to Windows XP SP2, not quite sure what's up with that yet.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/gadget/u_ether.h b/drivers/usb/gadget/u_ether.h
index 8abf197..0d1f7ae 100644
--- a/drivers/usb/gadget/u_ether.h
+++ b/drivers/usb/gadget/u_ether.h
@@ -34,10 +34,13 @@
 /*
  * This represents the USB side of an "ethernet" link, managed by a USB
  * function which provides control and (maybe) framing.  Two functions
- * in different configurations could share the same ethernet link/netdev.
+ * in different configurations could share the same ethernet link/netdev,
+ * using different host interaction models.
  *
- * There is currently a limitation that one instance of this function
- * may be present in any given configuration.
+ * There is a current limitation that only one instance of this link may
+ * be present in any given configuration.  When that's a problem, network
+ * layer facilities can be used to package multiple logical links on this
+ * single "physical" one.
  */
 struct gether {
 	struct usb_function		func;
@@ -107,4 +110,18 @@
 int geth_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);
 int ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);
 
+#ifdef CONFIG_USB_ETH_RNDIS
+
+int rndis_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);
+
+#else
+
+static inline int
+rndis_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN])
+{
+	return 0;
+}
+
+#endif
+
 #endif /* __U_ETHER_H */