USB: Correct CONFIG variable typo.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/ether.c

@@ -259,7 +259,7 @@ static struct usb_configuration rndis_config_driver = {
 
 /*-------------------------------------------------------------------------*/
 
-#ifdef USB_ETH_EEM
+#ifdef CONFIG_USB_ETH_EEM
 static int use_eem = 1;
 #else
 static int use_eem;