By Balazs Koranyi and Anne Kauranen HELSINKI (Reuters) – The European Central Bank must continue to raise interest rates quickly to tame inflation and could reach a level that no longer stimulates the economy before Christmas, Finnish central bank chief Olli Rehn said in an interview. The ECB lifted rates by a combined 125 basis points in its past two meetings, the fastest pace of policy tightening on record, but inflation is still months from its peak, pointing to even more tightening from a bank that started hiking well after most of its top peers. “There is a case for taking a decision on a…