I am running arm64 FreeBSD on my Raspberry Pi 3 using the image .
I noticed that powerd(8) doesn't work because the bcm2835_cpufreq(4)
driver is missing. Further sleuthing suggests, that the image has been
built with the default kernel configuration (arm64/conf/GENERIC). I
see that special kernel configuration is provided for the Raspberry
Pi 2 in arm/conf/RPI2, how do I configure a kernel for the RPi 3 that
actually contains all the drivers I need?