pmp: require execute permission for HLVX accesses

[Maanvi212006]

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Why is this PR needed for the project?

HLVX accesses must require both read and execute permissions from PMP, as specified by the RISC-V Privileged Specification. Previously, HLVX accesses were checked as normal read accesses, allowing execution through read-only PMP regions.

This change forwards the HLVX flag to the PMP data interface and performs the permission check with both ACCESS_READ and ACCESS_EXEC.

Issue

fixes #3400

Are there limitations with the current state of this contribution?

This change only updates the PMP permission check for HLVX accesses. No additional verification tests are included in this PR.

[Maanvi212006]

Hii @JeanRochCoulon , the Verible / format (pull_request_target) is unrelated to my PR. The PR is ready for review. Thanks!

[cainria]

Indeed a PR is open to fix Verible #3403

[cainria]

#3403 was merged so Verible should pass if we restart the job or on your next push.

There is another issue, see #3415 -> merged

[Maanvi212006]

Hi @JeanRochCoulon a gentle ping!
Thanks