Add the binding document for the new brcmstb-avs-cpufreq driver.
Signed-off-by: NMarkus Mayer <mmayer@broadcom.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>