chore: fix use_cache flag (#2965)

Author: peri044

py/torch_tensorrt/ts/ptq.py

@@ -101,7 +101,7 @@ def __new__(cls, *args: Any, **kwargs: Any) -> Self:
                 ),
             )
 
-        if not cache_file:
+        if cache_file:
             if use_cache:
                 log(
                     Level.Debug,
@@ -112,8 +112,8 @@ def __new__(cls, *args: Any, **kwargs: Any) -> Self:
         else:
             if use_cache:
                 log(
-                    Level.Error,
-                    "Input cache file is None but use_cache is set to True in INT8 mode.",
+                    Level.Warning,
+                    "Input cache file is None but use_cache is set to True in INT8 mode. Ignoring use_cache flag in this run.",
                 )
 
         # Define attributes and member functions for the calibrator class