According to avherald.com, the aircraft was scheduled to land in Moscow (not Madrid, as reported by Reuters and others) and was "descending towards Moscow when the crew advised one of the FADEC...channels controlling the left hand engine (GE90) had failed. The aircraft continued normally for a safe landing on Sheremetyevo's runway 24L."
It doesn't sound like a big deal. The ENG EEC MODE checklist requires the crew to disconnect the autothrottle, retard the thrust levers to mid-position (probably not required if they were on descent and the thrust levers were at idle), select both EEC MODE switches off, then re-engage the autothrottle. Carry on!