Add AMD_APU architecture for Tuo-like systems (not a multi-arch CPU+GPU build)

[kulnaman]

Currently running variorum's GPU build on Tuolumne the power number are reported for GPU, but in reality these are number for the whole APU.
So instead of showing output as :

we should change the JSON field from GPU_{id} to APU-{id} for all variorum API's as there are no separate domain for CPU and GPU. This also means that there is only a need for GPU build and no need for CPU build as that requires HSMP/amd-energy.
I have tested variorum GPU build to get power and utilization numbers for CPU and its seems to be working. The above screenshots shows the power consumption of running GEMM on TWO CPU sockets using the variorum-get-power-json API.

[tpatki]

Thanks for testing this on Tuo, @kulnaman!

We need to internally support an APU representation, where both the current "CPU" and "GPU" build output the correct data. Also need to support variorum print power APIs, and something we need to consider for print/get energy APIs.