cpufreq for freescale mx51

Currently, only two operating points: 160Mhz and 800Mhz.
the operating points are tested on babbage 3.0

Signed-off-by: Yong Shen <yong.shen@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
10 files changed