USB GADGET/PERIPHERAL: g_file_storage Bulk-Only Transport compliance

Gadget can tell controller driver to ignore Clear-Feature(HALT_ENDPOINT)
This API change enables future support for Bulk-Only Transport compliance

Signed-off-by: David Lopo <lopo.david@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>