With cpufreq disabled, the CPU stays locked at the frequency set by the
bootloader. This severely degrades performance as the bootloader sets
the CPU at the lowest frequency by default.
Enable cpufreq for all subtargets and use the ondemand governor.
Tested bcm2708 on RPi0W. Tested bcm2709 and bcm2710 on RPi3.
Reported-by: Bryan Mayland <bmayland@capnbry.net>
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>