Refa: PARALLEL_DEVICES is a static parameter. (#6168)

### What problem does this PR solve?


### Type of change

- [x] Refactoring

rag/app/naive.py

@@ -128,8 +128,8 @@ class Docx(DocxParser):
 
 
 class Pdf(PdfParser):
-    def __init__(self, parallel_devices = None):
-        super().__init__(parallel_devices)
+    def __init__(self):
+        super().__init__()
 
     def __call__(self, filename, binary=None, from_page=0,
                  to_page=100000, zoomin=3, callback=None):
@@ -197,7 +197,7 @@ class Markdown(MarkdownParser):
 
 
 def chunk(filename, binary=None, from_page=0, to_page=100000,
-          lang="Chinese", callback=None, parallel_devices=None, **kwargs):
+          lang="Chinese", callback=None, **kwargs):
     """
         Supported file formats are docx, pdf, excel, txt.
         This method apply the naive ways to chunk files.
@@ -237,7 +237,7 @@ def chunk(filename, binary=None, from_page=0, to_page=100000,
         return res
 
     elif re.search(r"\.pdf$", filename, re.IGNORECASE):
-        pdf_parser = Pdf(parallel_devices)
+        pdf_parser = Pdf()
         if parser_config.get("layout_recognize", "DeepDOC") == "Plain Text":
             pdf_parser = PlainParser()
         sections, tables = pdf_parser(filename if not binary else binary, from_page=from_page, to_page=to_page,