ipq806x: set PERFORMANCE as the default cpufreq governor

ipq806x: set PERFORMANCE as the default cpufreq governor

Move default cpufreq governor from ONDEMAND to PERFORMANCE. The temp
increase is just 2°C and Watt usage the change is minimal in the order
of additional millwatt. The SoC and krait in general looks to suffer for
some problem with cache scaling. To have better system stability, force
cpu freq and cache freq to the max value supported by the system. This
follows mvebu platform where cpufreq is broken and cause minimal
temp/watt increase.

User can still tweak the governor to ondemand using sysfs entry if
needed.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
(cherry picked from commit 6f5ea752d7c95ba426ca21a6588cae8812bb3e7c)