* Private equity deal value $79 bln in Asia ex-Japan so far in 2018.: HONG KONG (Reuters) - Dealmaking by private equity firms in Asia has surged this year, data showed, underscoring their rising presence in the region’s otherwise stolid, tycoon-dominated M&A scene, backed by an unmatched warchest. Private equity-backed deals so far this year total $79 billion in Asia-Pacific excluding Japan, up 63 percent over the same period of last year and surpassing the $74 billion full-year record set in 2015, according to Refinitiv data.