USB: usb.h kernel-doc additions

Add kernel-doc entries in <linux/usb.h> for:

Warning(linux-2.6.22-git12//include/linux/usb.h:162): No description found for parameter 'intf_assoc'
Warning(linux-2.6.22-git12//include/linux/usb.h:268): No description found for parameter 'intf_assoc[USB_MAXIADS]'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>