USB: export the new ch11.h file to userspce

This patch (as1374) cleans up a few loose ends in the
include/linux/usb/ch11.h header file and exports it to userspace.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Eric Lescouet <Eric.Lescouet@virtuallogix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>