Fix DocBook build. Regression was introduced by gregkh-usb-usb-linux-usb_ch9h-becomes-linux-usb-ch9h.patch Tested by `make htmldocs`. Signed-off-by: Don Mullis <dwm@meer.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>