OpenEmbedded "poky" with some sysmocom specific modifications. Mostly used only up to sysmocom release 201310, but the "pyro" branch is still used for 201705
I edited the config through make menuconfig and then used
savedefconfig but the diff from our config to a minimal
defconfig is too big. So I enabled the temp sensors and i2c
by hand.
Fixes: SYS#1148