shill: Makes WiFi device get available wifi frequencies from kernel.

Plus a couple of whitespace fixes.  This CL is in preparation for
passing the list of wifi frequencies to a scan request.

BUG=chromium:222088
TEST=unittest and manual tests.  The manual tests consist of:
  - Start shill with log=-10/wifi.  On the target, in a shell window,
    do the following:
      o stop shill
      o shill --log-level=-10 --log-scopes=wifi
  - Wait five seconds (the code will do everything it needs to at
    startup).
  - Look in /var/log/net.log and verify the following:
      o Found frequency[xx] = yyyy
      o There should be several frequencies (at least in the open at Google).
      o 'xx' is a number, I'd expect it to start at 0.
      o 'yyyy' is a number in the 5000s or the 2000x.

Change-Id: I8f0526abc22a7e9e60fd964c96d05eb95fa10e78
Reviewed-on: https://gerrit.chromium.org/gerrit/49271
Reviewed-by: Wade Guthrie <wdg@chromium.org>
Tested-by: Wade Guthrie <wdg@chromium.org>
Commit-Queue: Wade Guthrie <wdg@chromium.org>
diff --git a/nl80211_message.h b/nl80211_message.h
index ae65319..d9526a8 100644
--- a/nl80211_message.h
+++ b/nl80211_message.h
@@ -243,7 +243,7 @@
   static const uint8_t kCommand;
   static const char kCommandString[];
 
-  GetWiphyMessage() : Nl80211Message(kCommand, kCommandString) {}
+  GetWiphyMessage();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GetWiphyMessage);