* University-run, state-backed China firm extends M&A drive * Beijing building presence in chip and data industry * President Xi's alma mater linked to influential firms * US scrutiny in view after Micron purchase queried SINGAPORE/TAIPEI, Oct 1 (Reuters) - A billion-dollar Chinese plan to invest in Western Digital Corp is designed to plug the U.S. data storage firm into a network of influential China tech players carefully constructed by Tsinghua University, the alma mater of President Xi Jinping. For $3.8 billion, a unit of state-owned Tsinghua Holdings Co will get a 15 percent stake in Western Digital. What Tsinghua, run by a university committee, hopes to get is the latest in a string of domestic and foreign footholds in data storage and the chip market, an area deemed of... More