https://wmatrix.googleplex.com/unfiltered?suites=wifi_matfunc&tests=network_WiFi_Reset&days_back=45&releases=64&platforms=elm,daisy,kevin,peach_pi

This issue is only on elm devices. Reset fails after 7 attempts. 
Other devices with Marvel wifi chipset do not encounter this. 

Sample Failure 

Traceback (most recent call last):
  File "/usr/local/autotest/client/common_lib/test.py", line 631, in _exec
    _call_test_function(self.execute, *p_args, **p_dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 831, in _call_test_function
    return func(*args, **dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 495, in execute
    dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 362, in _call_run_once_with_retry
    postprocess_profiled_run, args, dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 400, in _call_run_once
    self.run_once(*args, **dargs)
  File "/usr/local/autotest/server/site_tests/network_WiFi_Reset/network_WiFi_Reset.py", line 103, in run_once
    client.wifi_if)
TestFail: Failed to reset device mlan0