Add XNNPACK int8 (8da8w): WER within -1.0/+0.3 of fp32 on en/de/es/pl/fr/zh

.gitattributes

@@ -40,3 +40,4 @@ mlx/whisper_base_mlx_bf16.pte filter=lfs diff=lfs merge=lfs -text
 mlx/whisper_base_mlx_int8.pte filter=lfs diff=lfs merge=lfs -text
 vulkan/whisper_base_vulkan_fp16.pte filter=lfs diff=lfs merge=lfs -text
 vulkan/whisper_base_vulkan_int8.pte filter=lfs diff=lfs merge=lfs -text
+xnnpack/whisper_base_xnnpack_int8.pte filter=lfs diff=lfs merge=lfs -text

xnnpack/whisper_base_xnnpack_int8.pte

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:12b8c41377902805374eed13c73259b1b44bbc9a472eccb45cc6d7d5c8686831
+size 266797312