DUBAI (Reuters) - Qatar Telecom (Qtel) has raised its stake in Kuwait's Wataniya to 92.1 percent following the close of its tender offer. The Qatari firm, which operates in 16 countries across the Middle East, Africa and Asia, paid 519.1 million Kuwaiti dinars ($1.8 billion) at 2.6 dinars per share to raise its stake from 52.5 percent, it said in a statement on Sunday. It did not specify from whom it bought the shares, but on Saturday, sources familiar with the situation told Reuters that the Kuwait Investment Authority (KIA) had agreed to sell its 23.5 percent stake in Kuwait's No. ...