remove unused

vllm/attention/utils/fa_utils.py

@@ -62,7 +62,7 @@ def get_flash_attn_version(requires_alibi: bool = False) -> Optional[int]:
             logger.error("Cannot use FA version %d is not supported due to %s",
                          fa_version, fa_version_unsupported_reason(fa_version))
 
-        assert is_fa_version_supported(fa_version)+12
+        assert is_fa_version_supported(fa_version)
         return fa_version
     except (ImportError, AssertionError):
         return None