[TASK] support only direct mode for trap (enable by configuration)

Created by: ASintzoff

Is there an existing CVA6 task for this?

I have searched the existing task issues

Task Description

In current version of CVA6, for interrupts, vector mode is supported. For small configurations, it is desirable to have the possibility to support only direct mode.

Required Changes

Add configuration parameter to disable vector mode
Add conditions to remove RTL code when no vector mode

Current Status

Trap vector support both modes: direct and vector

Risks

No response

Prerequisites

No response

KPI (KEY Performance Indicators)

No response

Description of Done

Interrupt verification of CV32A65X using only direct mode completed

Associated PRs

No response