audio : refactoring of compress passthrough changes.

Add DTS fomat support for compress passthrough.
Code clean-up and refactoring.
Keep Alive fixes.
Disable Compress Passthrough and DAP by default.

Change-Id: Id0b67630077e06284b8a396be69ebe0c72747c90
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index d60d67c..8922a4e 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -1642,6 +1642,9 @@
         platform_acdb_init(my_data);
     }
 
+    /* init keep-alive for compress passthru */
+    audio_extn_keep_alive_init(adev);
+
 acdb_init_fail:
 
     set_platform_defaults(my_data);