cpufreq: qcom-cpufreq-hw: add support for 4 freq domains

Add support for up to 4 frequency domains as used on new
platforms.

Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>