ARM: mxs: init cpufreq-dt device

Adds cpufreq-dt platform device for mxs pm init.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
ARM: dts: imx28 cpufreq-dt frequencies

This patch adds the operating points for i.MX28 to get cpufreq-dt
working.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
ARM: dts: imx23 cpufreq-dt frequencies

This patch adds the operating points for i.MX23 to get cpufreq-dt
working.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>