configs: reduce the gain of headset mic for QRD device

The input of headset mic is too high, and will be easily
saturated in dsp,  improve it with lower gain.

Change-Id: Ic6b7d5ef92e8ab159945bb99e0d3082b14924f30
diff --git a/configs/msmnile/mixer_paths_tavil.xml b/configs/msmnile/mixer_paths_tavil.xml
index a19c667..b101e3a 100644
--- a/configs/msmnile/mixer_paths_tavil.xml
+++ b/configs/msmnile/mixer_paths_tavil.xml
@@ -2302,6 +2302,11 @@
         <path name="amic2" />
     </path>
 
+    <path name="voice-headset-mic-qrd">
+        <path name="amic2" />
+        <ctl name="DEC0 Volume" value="84" />
+    </path>
+
     <path name="speaker-and-headphones">
         <path name="headphones" />
         <path name="speaker" />