USB: Added USB_ETH_RNDIS to use instead of CONFIG_USB_ETH_RNDIS

If g_ether and g_multi are both built CONFIG_USB_ETH_RNDIS symbol
may be redefined in the later and, whats even worse, g_ether's settings
may affect g_multi's.  This adds a USB_ETH_RNDIS symbol defined at the
beginning of ether.c and multi.c according toproper KConfig settings.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
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 91b39ff..fd55f45 100644
--- a/drivers/usb/gadget/u_ether.h
+++ b/drivers/usb/gadget/u_ether.h
@@ -112,7 +112,7 @@
 int ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);
 int eem_bind_config(struct usb_configuration *c);
 
-#ifdef CONFIG_USB_ETH_RNDIS
+#ifdef USB_ETH_RNDIS
 
 int rndis_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);