net: selftests: clean up tools/testing/selftests/net/lib/py/utils.py

This patch improves the utils.py module by removing unused imports
(errno, random), simplifying the fd_read_timeout() function by
eliminating unnecessary else clause, and cleaning up code style in the
defer class constructor.

Additionally, it renames the parameter in rand_port() from 'type' to
'stype' to avoid shadowing the built-in Python name 'type', improving
code clarity and preventing potential issues.

These changes enhance code readability and maintainability without
affecting functionality.

Signed-off-by: Breno Leitao <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

tools/testing/selftests/net/lib/py/utils.py

···
 # SPDX-License-Identifier: GPL-2.0
 
-import errno
 import json as _json
 import os
-import random
 import re
 import select
 import socket
···
     rlist, _, _ = select.select([fd], [], [], timeout)
     if rlist:
         return os.read(fd, 1024)
-    else:
-        raise TimeoutError("Timeout waiting for fd read")
+    raise TimeoutError("Timeout waiting for fd read")
 
 
 class cmd:
···
 
 class defer:
     def __init__(self, func, *args, **kwargs):
-        global global_defer_queue
-
         if not callable(func):
             raise Exception("defer created with un-callable object, did you call the function instead of passing its name?")
 
···
     return cmd_obj
 
 
-def rand_port(type=socket.SOCK_STREAM):
+def rand_port(stype=socket.SOCK_STREAM):
     """
     Get a random unprivileged port.
     """
-    with socket.socket(socket.AF_INET6, type) as s:
+    with socket.socket(socket.AF_INET6, stype) as s:
         s.bind(("", 0))
         return s.getsockname()[1]