Add support for Zilsd and Zcmlsd extensions

[lavanyajagan]

Description

Adding Support for Zilsd and Zcmlsd Extensions presented here:

Related Issues

The related PRs

• riscv-config support for the extension merged in dev PR
• riscv-isa-sim support for the extension available in master : commit id
• SAIL PR
• riscv-ctg PR
• riscv-isac PR
• Sample test env

This PR is depedent on the merging of the above PRs

Update to/for Ratified/Unratified Extensions or to framework

• [ ] Ratified
• [x] Unratified
• [ ] Framework

List Extensions

The unratified spec document: https://github.com/riscv/riscv-zilsd/blob/main/zilsd.adoc

Reference Model Used

• [x] SAIL
• [x] Spike
• [ ] Other - < SPECIFY HERE >

Mandatory Checklist:

• [x] All tests are compliant with the test-format spec present in this repo ?
• [x] Ran the new tests on RISCOF with SAIL/Spike as reference model successfully ?
• [x] Ran the new tests on RISCOF in coverage mode
• [x] Link to Google-Drive folder containing the new coverage reports (See this for more info): https://github.com/vyoma-systems/zilsd/coverage
• [x] Link to PR in RISCV-ISAC from which the reports were generated : https://github.com/riscv-software-src/riscv-isac/pull/92
• [ ] Changelog entry created with a minor patch

Optional Checklist:

• [x] RISCV-V CTG PR link if tests were generated using it : https://github.com/riscv-software-src/riscv-ctg/pull/117
• [x] Were the tests hand-written/modified ? No
• [x] Have you run these on any hard DUT model ? Please specify name and provide link if possible in the description We have run the tests on spike and sail supporting the extensions https://github.com/vyoma-systems/zilsd
• [] If you have modified arch_test.h Please provide a detailed description of the changes in the Description section above.