usb: core: hub.c Remove one to many n's in a word.

The Patch below removes one to many "n's" in a word..

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: linux-usb@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>