wayne-common: Remove default sampling rate and channel entries for bt…

… a2dp

 -Remove default setting of sampling rate to 48K and stereo channel
  for bt a2dp as support for multiple sampling rates and channels
  over a2dp is added and being set from hal.

Change-Id: I8a40182af0d97b31b136a1928cbbe6f728eb950f

audio/mixer_paths.xml

@@ -2318,8 +2318,6 @@
     </path>
 
     <path name="bt-a2dp">
-        <ctl name="BT SampleRate" value="KHZ_48" />
-        <ctl name="AFE Input Channels" value="Two" />
         <ctl name="SLIM7_RX ADM Channels" value="Two" />
     </path>