SUMMARY:
I wanted to create a PR showing users how they can add more mappings to
AWQ to account for more models. Turns out qwen has the exact same as
Llama, so I added one for Phi as well. I also updated the naming and
used the infer pattern employed in SmoothQuant, rather than requiring
user to set it

TEST PLAN:
`examples/awq/llama_example.py` works on this branch for 

```python
MODEL_ID = "microsoft/Phi-4-mini-reasoning"
```


TODOs:
- [x] Merge in after #1451 lands

---------

Signed-off-by: Brian Dellabetta <bdellabe@redhat.com>

… balance layer input length (vllm-project#1451)

### Summary
We are hitting an edge case in AWQ we had not previously hit with the
initial Llama/Qwen testing models. When a smooth layer's # of
output_features does not match a balance layer's # of input_features,
the code as it is currently will error out when trying to update the
smooth layer's weights with `weights.div(scales)`, due to a shape
mismatch error. We are hitting this in vllm-project#1440 for Phi3 models, which
include a mapping between the fused `qkv_proj` smooth layer and `o_proj`
balance layer in AutoAWQ (see
[here](https://github.com/casper-hansen/AutoAWQ/blob/main/awq/models/phi3.py#L51-L57)).

The resolution in AutoAWQ is to only use the last rows of the smooth
layer so that the shapes line up, as shown
[here](https://github.com/casper-hansen/AutoAWQ/blob/main/awq/quantize/scale.py#L123).
This PR includes that update, and with vllm-project#1440 will allow Phi3 models to
be quantizable with AWQModifier. Like with v_proj -> o_proj, if shapes
don't match up, they will be excluded from resolved mappings. This
allows
[phi-3-mini](https://huggingface.co/microsoft/Phi-3-mini-128k-instruct/tree/main?show_file_info=model-00001-of-00002.safetensors)
to include the mapping because `qkv_proj out_features == 3*o_proj
in_features == 9216`, but excludes it from
[phi-3-medium](https://huggingface.co/microsoft/Phi-3-medium-128k-instruct/tree/main?show_file_info=model-00001-of-00006.safetensors)
which has `qkv_proj out_features == 7680` and `o_proj
in_features==5120`. If the mapping is included for phi-3-medium, the
model blows up with wikitext eval perplexities >2000. This
implementation was agreed upon with @anmarques .

PS: I also moved `mul` & `div` to `mul_` & `div_`, to avoid unnecessary
memory allocation.

-------------
### Test Plan
With these changes and with vllm-project#1440 , `examples/awq/llama_example.py`
works with `"microsoft/Phi-3-mini-128k-instruct"` and produces similar
results as when qkv_proj to o_proj mapping is included

Without mapping:

| Tasks  |Version|Filter|n-shot|    Metric     |   | Value |   |Stderr|
|--------|------:|------|-----:|---------------|---|------:|---|------|
|wikitext|      2|none  |     5|bits_per_byte  |↓  | 0.6474|±  |   N/A|
|        |       |none  |     5|byte_perplexity|↓  | 1.5664|±  |   N/A|
|        |       |none  |     5|word_perplexity|↓  |11.0201|±  |   N/A|

With mapping:

| Tasks  |Version|Filter|n-shot|    Metric     |   | Value |   |Stderr|
|--------|------:|------|-----:|---------------|---|------:|---|------|
|wikitext|      2|none  |     5|bits_per_byte  |↓  | 0.6482|±  |   N/A|
|        |       |none  |     5|byte_perplexity|↓  | 1.5672|±  |   N/A|
|        |       |none  |     5|word_perplexity|↓  |11.0527|±  |   N/A|

I also confirmed re-running with `meta-llama/Llama-3.2-3B-Instruct` and
`meta-llama/Llama-2-7b-hf` does not deviate in PPL scores from what is
currently on `main`

---------

Signed-off-by: Brian Dellabetta <bdellabe@redhat.com>

SUMMARY:
I wanted to create a PR showing users how they can add more mappings to
AWQ to account for more models. Turns out qwen has the exact same as
Llama, so I added one for Phi as well. I also updated the naming and
used the infer pattern employed in SmoothQuant, rather than requiring
user to set it

TEST PLAN:
`examples/awq/llama_example.py` works on this branch for 

```python
MODEL_ID = "microsoft/Phi-4-mini-reasoning"
```


TODOs:
- [x] Merge in after vllm-project#1451 lands

---------

Signed-off-by: Brian Dellabetta <bdellabe@redhat.com>