audiopolicy: add support to load custom audiopolicymanager.

This change provides a mechanism to load a custom implementation of
AudioPolicyManager.
If custom library is present load that otherwise fallback to default
AudioPolicyManager.

This custom implementation should reside under system_ext or product
partition and should be compliant to xTS test suites.

- To use this create a library viz. libaudiopolicymanagericustom.so by
  extending AudioPolicyManager in system_ext or product partition,
  expose createAudioPolicyManager & destroyAudioPolicyManager methods
  to return custom AudioPolicyManager instance.

Bug: 120198776
Test: make

Change-Id: I0df7c390fe29f56378d4b90ca5ab559302770419
diff --git a/services/audiopolicy/service/Android.bp b/services/audiopolicy/service/Android.bp
index 8cb1b59..8186da9 100644
--- a/services/audiopolicy/service/Android.bp
+++ b/services/audiopolicy/service/Android.bp
@@ -18,7 +18,7 @@
         "libaudioclient_aidl_conversion",
         "libaudiofoundation",
         "libaudiopolicy",
-        "libaudiopolicymanager",
+        "libaudiopolicymanagerdefault",
         "libaudioutils",
         "libbinder",
         "libcutils",