FelCor Lodging Trust Inc., which last year launched an effort to reposition its portfolio of hotels, has put 16 properties up for sale. Last year, the Irving-based company said it had identified a total of 40 hotels that would be sold as part of its repositioning strategy. Those include 72 percent of its suburban properties and 44 percent of its airport properties. The properties it will keep are in what it terms gateway cities that have relatively high barriers-to-entry. The 16 it put on the sales block represent the first of those 40.