audio: Add audio_policy.conf file

- Add audio policy.conf file for MSM8226 target
- Enable tunnel decode by default

Change-Id: Ib63f00b32834b5c2f9365c8ffba261ef36472abc
diff --git a/system.prop b/system.prop
index 393bc74..afa696f 100644
--- a/system.prop
+++ b/system.prop
@@ -32,7 +32,9 @@
 dev.pm.dyn_samplingrate=1
 
 ro.hdmi.enable=true
-lpa.decode=true
+tunnel.decode=true
+tunnel.audiovideo.decode=true
+lpa.decode=false
 lpa.use-stagefright=true
 
 #system props for the MM modules