Add smn(4) driver for AMD System Management Network
AMD Family 17h CPUs have an internal network used to communicate between
the host CPU and the PSP and SMU coprocessors. It exposes a simple
32-bit register space.
amdtemp(4): Add support for Family 17h temperature sensor
The sensor value is formatted similarly to previous models (same
bitfield sizes, same units), but must be read off of the internal
System Management Network (SMN) from the System Management Unit (SMU)