[Refactor] Remove `g_idx == -1` checks

[kylesayrs]

Background

• g_idx is a quantization parameter used when applying activation ordering using the GPTQ algorithm. This parameter is initialized to -1s. However, when GPTQ is applied, the parameter's value is set, and it is a bug to read the value before the value is calibrated by GPTQ (in the same way that it is a bug to read scales before they are calibrated).

Purpose

• Reduce runtime when using activation ordering
• Clean codebase of extra cases

Proposed Changes

• Remove all instances and cases of using g_idx full of negative ones from CT and LC

[rk119]

Hi @kylesayrs,

Can I work on this? :D

[brian-dellabetta]

Hi @rk119 , assigned it to you, thanks!