sunxi-cpu-freq: Tweak cpufreq limits

cpu-freq has 2 sets of limits, 1 called cpuinfo which indicates what the
minimum / maximum freq of the cpu is, and the 2nd set indicates between
which limits the governor should automatically scale.

This patch splits the setting of the 2 sets of limits, and adds a
SUNXI_SCALING_MIN Kconfig option to allow raising the minimum speed
the (ondemand) governor will use from the current 60 MHz, which is
unworkably slow IMHO, to something better, ie 408 MHz, which is the last
speed at which the cpu runs at its lowest voltage of 1.0 volt.

This patch keeps the default at 60 MHz, to avoid regressions in battery
use, but I would like to advocate people to try out 408 Mhz instead,
which not only makes the interactive feel of the device a lot better, it
likely also *saves* power since it will cause the cpu to reach an idle
state quicker, which will allow it to power down entire blocks, thus stopping
the constant (non speed dependent) leakage current of those blocks sooner,
while using aprox. the same amount of power to do the work (it uses more
power due to the higher clock, but does the work proportionally faster,
resulting in aprox. the same power use). This is the so called race to idle
trick.

While at it also fix the formatting of sun4i_cpufreq_init().

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Merge from linux-sunxi stage/sunxi-3.4

Merge Allwinner A1x SoC BSP code.