Integrate ALU/LSU into schnizo.

[LionelNoussi]

This integrates the changes made during the semester thesis of Lionel Noussi (lnoussi@ethz.ch).

I would recommend first merging these changes into a feature branch.

Features:

• New functional unit: ALU/LSU
• Reservation Station Slots split up into issue and result slots
• Support for two result ports into reservation station
• Support for instructions with two results in reservation station

Changes:

• iDMA and XFREP func3 OpCode hardcoded to 011
  • This needs new compiler support as well. A pre-compiled version is distributed on /usr/scratch2/vulcano/lnoussi/tools/riscv32-schnizo-llvm-funct3-011/bin
  • To recompile it yourself, see this fork of the llvm-project: https://github.com/LionelNoussi/llvm-project.git (snitch branch)