audio: Update comments for voice mics

Change-Id: I3fc888a4046a2b49bc887088750dd0e5be1c543c
diff --git a/audio/mixer_paths_0.xml.template b/audio/mixer_paths_0.xml.template
index d3d21f6..7753896 100644
--- a/audio/mixer_paths_0.xml.template
+++ b/audio/mixer_paths_0.xml.template
@@ -85,22 +85,26 @@
 
     <!-- Two mic -->
     <path name="voice-earpiece-mic">
-        <!-- Should be builtin and back mic -->
+        <!-- Should be main mic and back mic -->
+        <!-- Capture channel set to main mic -->
         <!-- Empty path -->
     </path>
 
     <path name="voice-earpiece-mic-wb">
-        <!-- Should be builtin and back mic -->
+        <!-- Should be main mic and back mic -->
+        <!-- Capture channel set to main mic -->
         <!-- Empty path -->
     </path>
 
     <path name="voice-speaker-mic">
-        <!-- Should be builtin and back mic -->
+        <!-- Should be main mic and back mic -->
+        <!-- Capture channel set to back mic -->
         <!-- Empty path -->
     </path>
 
     <path name="voice-speaker-mic-wb">
-        <!-- Should be builtin and back mic -->
+        <!-- Should be main mic and back mic -->
+        <!-- Capture channel set to back mic -->
         <!-- Empty path -->
     </path>