Update supported_hardware.md for TPU INT8 (vllm-project#16437)

Signed-off-by: Yang Wang <elainewy@meta.com>

Author: mgoin

docs/source/features/quantization/supported_hardware.md

@@ -62,7 +62,7 @@ The table below shows the compatibility of various quantization implementations
   * ❌
   * ✅︎
   * ❌
-  * ❌
+  * ✅︎
 - * FP8 (W8A8)
   * ❌
   * ❌