Split libmedia into libmedia and libaudioclient

This makes it so audioserver doesn't need to link against the entire libmedia,
which has dependencies on camera, ICU, OpenGL and other things that aren't
needed for audio.

Test: build/boot

Change-Id: I99ba1a3dc3b33ca9b3abd98e7519dbf228ee62af
diff --git a/services/audiopolicy/Android.mk b/services/audiopolicy/Android.mk
index 91cc3d2..5f02a98 100644
--- a/services/audiopolicy/Android.mk
+++ b/services/audiopolicy/Android.mk
@@ -30,7 +30,7 @@
     libutils \
     liblog \
     libbinder \
-    libmedia \
+    libaudioclient \
     libhardware_legacy \
     libserviceutility