staging/lustre/llite: Preparation to move /proc/fs/lustre/llite to sysfs

Add necessary infrastructure, add support for mountpoint
registration in /proc/fs/lustre/llite

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>