cpufreq cmdline handling

cpufreq cmdline handling

c/s 19147 adjust cpufreq cmdline handling, this patch is a complement
to c/s 19147.

In this patch:
1. add common para (governor independent para) handling;
2. change governor dependent para handling method, governor dependent
para will only be handled by the handler of that governor (not by all
governors);
3. add userspace governor dependent para handling;
4. change para name 'threshold' of ondemand governor to 'up_threshold'
since ondemand has only 'up_threshold', and conservative governor (will be
implemented later) has both 'up_threshold' and 'down_threshold';
5. change some coding style (c/s 19147, drivers/cpufreq/cpufreq.c) to
keep coordination with original drivers/cpufreq/cpufreq.c coding style;
(originally this file is ported from linux, we partly use linux coding style)

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>