Add comment of using same callback for start/stop advertising.
Add comment of using same callback for start/stop advertising.

Change-Id: Ice268e83e4f2ceb5053a0e03f73b877f548bd13b

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base