ARM: dts: imx27 cpufreq-cpu0 frequencies

Set operating-points for imx27. There is no regulator support, so the
voltages are 0. The frequencies should be the same for all imx27 boards,
so it is defined here and can be overwritten if necessary.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>