update network type less frequently (#1108)

old-commit-hash: 2cc0eb1ca0

selfdrive/thermald.py

@@ -192,6 +192,8 @@ def thermald_thread():
     if health is not None:
       usb_power = health.health.usbPowerMode != log.HealthData.UsbPowerMode.client
 
+    # get_network_type is an expensive call. update every 3s
+    if (count % int(3. / DT_TRML)) == 0:
       try:
         network_type = get_network_type()
       except subprocess.CalledProcessError: