Integrate RedMulE and NEureka as selectable HWPEs

[ricted98]

Add the two HWPEs in the HWPE subsystem and use a static selection signal to choose between them. Some important points are:

• Arrays of interfaces have been used to make the number of HWPEs a parameter
• Currently the peripherals support a single selection bit (https://github.com/pulp-platform/cluster_peripherals/pull/5), if we want to parametrize the whole design this can be discussed, otherwise the HWPE is currently hardcoded at 2 HWPEs when instantiated.

[yvantor]

• [ ] Avoid the unneeded muxing of all add and data signals

  • [ ] Check and evaluate other comments

  • [ ] Verify functionality with integration test

I think these were almost all covered?

[ricted98]

• [x] Avoid the unneeded muxing of all add and data signals
• [x] Check and evaluate other comments
• [x] Verify functionality with integration test

This is the current status. The functionality was verified only for RedMulE.

[ricted98]

I think this PR is ready for review and eventually merge. Related PRs are:

• cluster_peripherals: https://github.com/pulp-platform/cluster_peripherals/pull/5
• regression_tests: https://github.com/pulp-platform/regression_tests/pull/16

The current parametrization of the HWPE subsystem also allows the addition of more HWPEs if needed.

[ricted98]

I think it's all done.