Add libaudiofoundation.

Some classes, e.g. AudioGain, in libaudiofoundation, which are used by
libaudiopolicycomponent, will require libaudiofoundation as a shared
library to avoid link error when building.

Bug: 135621476
Test: make
Change-Id: I8732bdab37d8afd866fe03a74db3dc564fea1ad2
diff --git a/audio/core/all-versions/vts/functional/Android.bp b/audio/core/all-versions/vts/functional/Android.bp
index 88fdb5a..5e17ade 100644
--- a/audio/core/all-versions/vts/functional/Android.bp
+++ b/audio/core/all-versions/vts/functional/Android.bp
@@ -24,6 +24,7 @@
         "libxml2",
     ],
     shared_libs: [
+        "libaudiofoundation",
         "libfmq",
     ],
     header_libs: [