Add ratified Svadu extension

[ved-rivos]

Description

Add support for ratified Svadu extension.

Related Issues

Sail - riscv/sail-riscv#260

Ratified/Unratified Extensions

• Ratified
• Unratified

List Extensions

https://github.com/riscv/riscv-svadu

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 ?
• Ran the new tests on RISCOF in coverage mode
• Link to Google-Drive folder containing the new coverage reports (See this for more info): < SPECIFY HERE >
• Link to PR in RISCV-ISAC from which the reports were generated : < SPECIFY HERE >
• Changelog entry created with a minor patch

Optional Checklist:

• RISCV-V CTG PR link if tests were generated using it : < SPECIFY HERE >
• [ x] Were the tests hand-written/modified ?
• Have you run these on any hard DUT model ? Please specify name and provide link if possible in the description
• If you have modified arch_test.h Please provide a detailed description of the changes in the Description section above.

[ved-rivos]

The extension name is updated to Svhad now.

[UmerShahidengr]

Merged this one, as its equivalent ctg PR has already been approved.