configs: msm8937: update headset codec tx gain

Loopback test fails because headset codec tx gain is
higher than expected.

Reduce headset codec tx gain to appropriate value

Change-Id: I45a0b251c13493e3d163f28807c4ecff60e495c8
diff --git a/configs/msm8937/mixer_paths_sdm439_pm8953.xml b/configs/msm8937/mixer_paths_sdm439_pm8953.xml
index 5099fff..328701c 100644
--- a/configs/msm8937/mixer_paths_sdm439_pm8953.xml
+++ b/configs/msm8937/mixer_paths_sdm439_pm8953.xml
@@ -1255,12 +1255,17 @@
         <ctl name="HPHR" value="Switch" />
     </path>
 
-    <path name="headset-mic">
+    <path name="headset-mic-default">
         <path name="adc2" />
         <ctl name="ADC2 MUX" value="INP2" />
         <ctl name="IIR1 INP1 MUX" value="DEC1" />
     </path>
 
+    <path name="headset-mic">
+        <path name="headset-mic-default" />
+        <ctl name="DEC1 Volume" value="74" />
+    </path>
+
     <path name="sidetone-iir">
         <ctl name="IIR1 Enable Band1" value="1" />
         <ctl name="IIR1 Enable Band2" value="1" />
@@ -1304,7 +1309,7 @@
     </path>
 
     <path name="voice-headset-mic">
-        <path name="headset-mic" />
+        <path name="headset-mic-default" />
     </path>
 
     <path name="speaker-and-headphones">