StreamHalHidl: Use atomic_wp and make pointers const

Avoid concurrency issues with modification of wp.

Test: basic audio
Bug: 177278988
Change-Id: I5b968a1dad24e1d6c18260884d35c3170661da01
diff --git a/media/libaudiohal/Android.bp b/media/libaudiohal/Android.bp
index 482f40e..d9a7804 100644
--- a/media/libaudiohal/Android.bp
+++ b/media/libaudiohal/Android.bp
@@ -31,6 +31,7 @@
     header_libs: [
         "libaudiohal_headers",
         "libbase_headers",
+        "libmediautils_headers",
     ]
 }