Manages link fault signal (LFS).
module: extreme-lfs
+--rw link-fault-signaling
      +--rw rx?   enumeration
      +--rw tx?   enumeration
 
	 module: extreme-interface | | +--rw lfs:link-fault-signaling | | | +--rw lfs:rx? enumeration | | | +--rw lfs:tx? enumeration