usb: linux/usb/gadget.h: fix duplicated word in comment

Change the doubled word "in" to "be in" in a comment.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/20200715045701.22949-2-rdunlap@infradead.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/usb/gadget.h

@@ -731,7 +731,7 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
  * it will first disconnect().  The driver is also requested
  * to unbind() and clean up any device state, before this procedure
  * finally returns.  It's expected that the unbind() functions
- * will in in exit sections, so may not be linked in some kernels.
+ * will be in exit sections, so may not be linked in some kernels.
  */
 int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);