The regulator for U.S. housing finance giants Fannie Mae (FNMA.OB) and Freddie Mac (FMCC.OB) told the two firms on Wednesday to provide more support to low-income Americans taking out mortgages and refinancing home loans. The Federal Housing Finance Agency released goals for the two government-controlled firms for 2015-2017 that would advance agency chief Mel Watt’s aim to widen access to housing credit.