By Paul Sandle LONDON (Reuters) – British chip designer ARM Holdings said a slowdown in demand for Apple and Samsung smartphones was behind a smaller than expected rise in fourth-quarter royalty revenues. ARM, whose technology is in nearly every smartphone, reported processor royalties of $130.4 million, up 7 percent, but short of analyst forecasts of $137.9 million. The top-end smartphone market has showed signs of reaching saturation, with Apple and Samsung, both ARM customers, last month reporting lower than expected sales of the iPhone 5S and Galaxy S4 phones in the holiday season.