Nikkei flat as earnings, central bank meetings cap risk appetite

* Market focused on central banks' policy meetings * Canon, Fanuc among companies reporting earnings Mon * Volume may stay low before Golden Week holidays - analysts By Ayai Tomisawa TOKYO, April 27 (Reuters) - Japanese stocks were flat in a choppy Monday morning as investors were cautious amid the earnings season and ahead of some key events later this week, including central bank meetings in Japan and the United States. The Bank of Japan is expected to hold off on expandin