Add an imx6q-cpufreq driver for Freescale i.MX6Q SoC to handle the
hardware specific frequency and voltage scaling requirements.

The driver supports module build and is instantiated by the platform
device/driver mechanism, so that it will not be instantiated on other
platforms, as IMX is built with multiplatform support.
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
Reviewed-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>