* Q1 net profit 512.1 mln dhs vs 494.9 mln dhs yr-ago - statement * Q1 provisions 44 mln dhs vs 127 mln dhs yr-ago * Q1 net interest margin 2.80 pct vs 3.06 pct in yr-ago period (Changes dateline, adds detail and context) ABU DHABI, May 12 (Reuters) -...