hotplug: consider current freq in for cpu_up()

When we decide to online one core, we should
also consider its current parent core. It may
happen that one core could be onlined while
the parent core is on a very low frequency and
just has a high load due that.

Also enable the full frequency table with the
last step (1300 mhz).

Signed-off-by: Blechd0se <alex.christ@hotmail.de>
hotplug: make smarter choices of offlining

Hotplug now messures the load on the ready for
offlining cores and finds the smallest.
This is an approach to don't migrate to stress
intensive tasks to the parent cores and offline
the core, which has really nothing to do.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>