[TASK] Remove halt signal from frontend.sv when accelerator not enabled

Placeholder github Source User
2026-03-14T02:20:04Z

### Is there an existing CVA6 task for this?

- [x] I have searched the existing task issues

### Task Description

The frontend's PC update logic uses the `halt_i` signal when `set_pc_commit_i` is raised, but after inspecting the RTL, these two signals are never raised at the same time (except for when accelerator is enabled) so there is no need to check `halt_i` when `set_pc_commit_i` is raised. Potential PR to solve this: https://gitlab.eclipse.org/openhw-group/backup-20260329/cva6/-/merge_requests/3193

### Required Changes

Described in https://gitlab.eclipse.org/openhw-group/backup-20260329/cva6/-/merge_requests/3193.

### Current Status

On hold for verification team.

### Risks

_No response_

### Prerequisites

_No response_

### KPI (KEY Performance Indicators)

_No response_

### Description of Done

Verification team checks that PR does not introduce any bugs.

### Associated PRs

_No response_