By Stephen Nellis SAN FRANCISCO (Reuters) -Cerebras Systems, a Silicon Valley startup aiming to take on Nvidia by producing a dinner-plate-sized AI computing chip, on Tuesday said it raised $1.1 billion and added 1789 Capital, the venture firm where Donald Trump Jr. is a partner, as an investor. Cerebras said the funding round, which was led by Fidelity Management & Research Co and Atreides Management, brings the company's valuation to $8.1 billion. The deal added investors Tiger Global, Valor Equity Pa ...