Fix init sequence for BT AV sink.

BTA_AvEnable_Sink() was being called to early causing
a crash loop when the BT AV_SINK was included. This patch
changes up the init sequence to match that of the av
source. Also, rename a few constants for clarity.

Change-Id: I3e6a7e22a2643eeceb4afc082979d1d9967b0b99
diff --git a/btif/src/btif_dm.c b/btif/src/btif_dm.c
index a317a94..5b86ab4 100644
--- a/btif/src/btif_dm.c
+++ b/btif/src/btif_dm.c
@@ -238,6 +238,7 @@
 extern UINT16 bta_service_id_to_uuid_lkup_tbl [BTA_MAX_SERVICE_ID];
 extern bt_status_t btif_hf_execute_service(BOOLEAN b_enable);
 extern bt_status_t btif_av_execute_service(BOOLEAN b_enable);
+extern bt_status_t btif_av_sink_execute_service(BOOLEAN b_enable);
 extern bt_status_t btif_hh_execute_service(BOOLEAN b_enable);
 extern bt_status_t btif_hf_client_execute_service(BOOLEAN b_enable);
 extern bt_status_t btif_mce_execute_service(BOOLEAN b_enable);
@@ -264,6 +265,10 @@
          {
               btif_av_execute_service(b_enable);
          }break;
+         case BTA_A2DP_SINK_SERVICE_ID:
+         {
+            btif_av_sink_execute_service(b_enable);
+         }break;
          case BTA_HID_SERVICE_ID:
          {
               btif_hh_execute_service(b_enable);