msm: cpufreq: Add support for CPU clocks and msm-cpufreq device

Add support for using clock APIs to do CPU/L2 frequency scaling. When clock
APIs are used to control CPU/L2 frequencies, the cpufreq driver must handle
the CPU -> L2 -> DDR bandwidth voting. Use a msm-cpufreq device to provide
the per SoC list of CPU frequencies and their L2/DDR bandwidth mapping
information.

If CPU/L2 clocks are not available, fallback to using acpuclock APIs. We
eventually want to remove the use of non-standard acpuclock APIs.

Change-Id: I2c4e2c3967d73e8cdbd9833f3cb36f3d75e27b4a
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>