[libre-riscv-dev] minor reorg of SoC repo

[Luke Kenneth Casson Leighton]

hi daniel,

i moved the scoreboard code to the soc repo, and did a small reorg,
adding a top-level Makefile and matching setup.py.  you should run
"sudo bash; python3 setup.py develop" or "sudo bash; make install".

i also reorganised the TLB files, and you will see that i fixed
test_address_encoder.py to run properly with the new layout, all the
unit tests need to be modified to conform with that pattern.

if anyone wants to help with that, do say so.

l.