This adds new at91 utmi clock implementation using common clk framework.

This clock is a pll with a fixed factor (x40).
It is used as a source for usb clock.
Signed-off-by: NBoris BREZILLON <b.brezillon@overkiz.com>
Acked-by: NMike Turquette <mturquette@linaro.org>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>