[doc] Update x86 CPU-inference installation doc to reflect optionality of AVX512f (#22707)

Signed-off-by: Sooraj S <94284954+sooraj-satheesh@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Co-authored-by: Li, Jiang <bigpyj64@gmail.com>

docs/getting_started/installation/cpu/x86.inc.md

@@ -6,7 +6,7 @@ vLLM supports basic model inferencing and serving on x86 CPU platform, with data
 # --8<-- [start:requirements]
 
 - OS: Linux
-- CPU flags: `avx512f`, `avx512_bf16` (Optional), `avx512_vnni` (Optional)
+- CPU flags: `avx512f` (Recommended), `avx512_bf16` (Optional), `avx512_vnni` (Optional)
 
 !!! tip
     Use `lscpu` to check the CPU flags.
@@ -28,7 +28,7 @@ vLLM supports basic model inferencing and serving on x86 CPU platform, with data
 [https://gallery.ecr.aws/q9t5s3a7/vllm-cpu-release-repo](https://gallery.ecr.aws/q9t5s3a7/vllm-cpu-release-repo)
 
 !!! warning
-    If deploying the pre-built images on machines only contain `avx512f`, `Illegal instruction` error may be raised. It is recommended to build images for these machines with `--build-arg VLLM_CPU_AVX512BF16=false` and `--build-arg VLLM_CPU_AVX512VNNI=false`.
+    If deploying the pre-built images on machines without `avx512f`, `avx512_bf16`, or `avx512_vnni` support, an `Illegal instruction` error may be raised. It is recommended to build images for these machines with the appropriate build arguments (e.g., `--build-arg VLLM_CPU_DISABLE_AVX512=true`, `--build-arg VLLM_CPU_AVX512BF16=false`, or `--build-arg VLLM_CPU_AVX512VNNI=false`) to disable unsupported features. Please note that without `avx512f`, AVX2 will be used and this version is not recommended because it only has basic feature support.
 
 # --8<-- [end:pre-built-images]
 # --8<-- [start:build-image-from-source]
@@ -37,6 +37,7 @@ vLLM supports basic model inferencing and serving on x86 CPU platform, with data
 docker build -f docker/Dockerfile.cpu \
         --build-arg VLLM_CPU_AVX512BF16=false (default)|true \
         --build-arg VLLM_CPU_AVX512VNNI=false (default)|true \
+        --build-arg VLLM_CPU_DISABLE_AVX512=false (default)|true \ 
         --tag vllm-cpu-env \
         --target vllm-openai .