Add m extension control and hazard

[tandr3w]

Close #245
Updated hazard unit to allow for DIV
Updated execute to select the MUL or DIV module instead of the ALU when needed
Added mul and div instructions to the interface between decode and execute

Note that I didn't actually use div_cancel since it wasn't in the diagram in the planning doc. Also, it seems unnececssary after thinking about it a little? Since a branch instruction should never be in ex at the same time as a div.

I also assumed that the modules would look like the diagrams, and I might've accidentally done some of the integration work as well since I didn't really know how to separate it

[DanielTaoHuang123]

connect is_div and is_mul to the feature flags; everything else seems OK

[DanielTaoHuang123]

pretty good overall; fix the two commented lines and resolve conflict and I think it will be good to merge

[DanielTaoHuang123]

probably want to change this logic from OR to AND, since when running RV32M riscof test both mul and div are tested; if only one of them is enabled the other reports error

[tandr3w]

I fixed the two comments and rebased but we probably need to wait for the decoder and mul/div unit to be done before merging.

[github-actions]

🔧 DE1-SoC Synthesis Report Summary Diff

• RV32I

  1. Fitter Summary

     @@ -1,4 +1,4 @@
     -Fitter Status : Successful - Mon Aug 31 14:11:06 2026
     +Fitter Status : Successful - Tue Sep  1 01:14:53 2026
      Quartus Prime Version : 25.1std.0 Build 1129 10/21/2025 SC Lite Edition
      Revision Name : utoss-risc-v
      Top-level Entity Name : top

  2. Fitter by entity
     No changes detected

  3. Timing
     No changes detected

• RV32IB

  1. Fitter Summary

     @@ -1,4 +1,4 @@
     -Fitter Status : Successful - Mon Aug 31 14:11:22 2026
     +Fitter Status : Successful - Tue Sep  1 01:14:48 2026
      Quartus Prime Version : 25.1std.0 Build 1129 10/21/2025 SC Lite Edition
      Revision Name : utoss-risc-v
      Top-level Entity Name : top

  2. Fitter by entity
     No changes detected

  3. Timing
     No changes detected

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Comparing synthesis results from main branch vs. this PR