[PATCH dpdk] pmdinfogen: fix warning with python 3.14

[Robin Jarry <rjarry@redhat.com>]

Fix the following warning seen on Fedora 43 with Python 3.14:

 buildtools/pmdinfogen.py:118: DeprecationWarning: Due to '_pack_', the
 'rte_pci_id' Structure will use memory layout compatible with MSVC
 (Windows). If this is intended, set _layout_ to 'ms'. The implicit
 default is dep recated and slated to become an error in Python 3.19.

Use the struct module which is simpler and assumes everything is packed
by default.

There is no change in the output of dpdk-pmdinfo.py before and after
this patch.

Link: https://docs.python.org/3/library/struct.html
Signed-off-by: Robin Jarry <rjarry@redhat.com>
---
 buildtools/pmdinfogen.py | 42 +++++++++++-----------------------------
 1 file changed, 11 insertions(+), 31 deletions(-)

diff --git a/buildtools/pmdinfogen.py b/buildtools/pmdinfogen.py
index 63e0a8b364a8..4401106f0bf5 100755
--- a/buildtools/pmdinfogen.py
+++ b/buildtools/pmdinfogen.py
@@ -4,9 +4,9 @@
 # Copyright (c) 2020 Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
 
 import argparse
-import ctypes
 import json
 import re
+import struct
 import sys
 import tempfile
 
@@ -110,24 +110,6 @@ def find_by_name(self, name):
         return None
 
 
-def define_rte_pci_id(is_big_endian):
-    base_type = ctypes.LittleEndianStructure
-    if is_big_endian:
-        base_type = ctypes.BigEndianStructure
-
-    class rte_pci_id(base_type):
-        _pack_ = True
-        _fields_ = [
-            ("class_id", ctypes.c_uint32),
-            ("vendor_id", ctypes.c_uint16),
-            ("device_id", ctypes.c_uint16),
-            ("subsystem_vendor_id", ctypes.c_uint16),
-            ("subsystem_device_id", ctypes.c_uint16),
-        ]
-
-    return rte_pci_id
-
-
 class Driver:
     OPTIONS = [
         ("params", "_param_string_export"),
@@ -166,26 +148,24 @@ def _load_pci_ids(image, table_name_symbol):
         if not table_symbol:
             raise Exception("PCI table declared but not defined: %d" % table_name)
 
-        rte_pci_id = define_rte_pci_id(image.is_big_endian)
+        if image.is_big_endian:
+            fmt = ">"
+        else:
+            fmt = "<"
+        fmt += "LHHHH"
 
         result = []
         while True:
-            size = ctypes.sizeof(rte_pci_id)
+            size = struct.calcsize(fmt)
             offset = size * len(result)
             data = table_symbol.get_value(offset, size)
             if not data:
                 break
-            pci_id = rte_pci_id.from_buffer_copy(data)
-            if not pci_id.device_id:
+            _, vendor, device, ss_vendor, ss_device = struct.unpack_from(fmt, data)
+            if not device:
                 break
-            result.append(
-                [
-                    pci_id.vendor_id,
-                    pci_id.device_id,
-                    pci_id.subsystem_vendor_id,
-                    pci_id.subsystem_device_id,
-                ]
-            )
+            result.append((vendor, device, ss_vendor, ss_device))
+
         return result
 
     def dump(self, file):
-- 
2.51.1