staging: lustre: obd: restore linkea support

Original linkea was only used for the lustre server code
so it was removed from the upstream client. Now it needs
to be restored for client work that uses this infrastructure.

Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>