m7 / dlx: cpufreq: Fix generation of uevents for governor changes

Prior to this change we were trying to generate a uevent on a
ktype that has no kset specified.  Since it had no kset specified,
the object hierarchy was traversed until we found a kset.  The
closest parent with a kset is the devices kobject.

The devices kset filters all uevents hat do not come from the
devices ktype.  Therefore it was filtering the governor change
uevents.

Create a new kset that has no filtering rules.

This is where it gets hacky.  Kobjects are supposed to define
their kset before initialization and then the kobject lib
takes care of managing all the kobjects correctly.

To maintain sysfs compatibility, we want our global_kobject
to be at

/sys/devices/system/cpu/cpufreq

If we attempt to create a new kset called cpufreq and its
kobject, we still cannot generate uevents because this kobject
does not itself use the kset's filtering rules.

Creating a kset in some other location and then trying to
create a kobject in the cpu_subsys hierarchy which is also
in this kset in another location causes the kernel to crash
(very strange things happen when you try to store to attributes).

The same crash happens if you build the kset hierarchy
correctly in some other location and then try to link the
kobject into the cpu_subsys.

What does work, but is wrong, is to reach into the kobject
after initialization and set a kset object.

Change-Id: I3aeaaf4558bfb42089a17a614f780d89be1c6380