treewide: fix remaining uses of threading camel case methods

The threading camel case methods were deprecated in [1]. A previous
pyserial PR [2] fixed a bunch of these warnings, but missed a few.

Fix the remaining setName() DeprecationWarnings by using the
appropriate name attribute instead.

[1] https://github.com/python/cpython/pull/25174
[2] https://github.com/pyserial/pyserial/pull/643

Signed-off-by: Bastian Krause <bst@pengutronix.de>

serial/rfc2217.py

diff --git a/serial/rfc2217.py b/serial/rfc2217.py
index c52bf52..caedea4 100644
--- a/serial/rfc2217.py
+++ b/serial/rfc2217.py
@@ -461,7 +461,7 @@
         self.is_open = True
         self._thread = threading.Thread(target=self._telnet_read_loop)
         self._thread.daemon = True
-        self._thread.setName('pySerial RFC 2217 reader thread for {}'.format(self._port))
+        self._thread.name = 'pySerial RFC 2217 reader thread for {}'.format(self._port)
         self._thread.start()
 
         try:    # must clean-up if open fails

serial/urlhandler/protocol_cp2110.py

diff --git a/serial/urlhandler/protocol_cp2110.py b/serial/urlhandler/protocol_cp2110.py
index ce5b037..620162f 100644
--- a/serial/urlhandler/protocol_cp2110.py
+++ b/serial/urlhandler/protocol_cp2110.py
@@ -100,7 +100,7 @@
             self.is_open = True
             self._thread = threading.Thread(target=self._hid_read_loop)
             self._thread.daemon = True
-            self._thread.setName('pySerial CP2110 reader thread for {}'.format(self._port))
+            self._thread.name = 'pySerial CP2110 reader thread for {}'.format(self._port)
             self._thread.start()
 
     def from_url(self, url):