AudioAttributes: Fix Builder.setFlags()

AudioAttributes.Builder.setFlags() is a public method and should only
allow to set public flags

Test: CTS AudioAttributesTest
Change-Id: Ib75e3487f5297f6a200ffe326c53a0f58458b51f

media/java/android/media/AudioAttributes.java

@@ -710,7 +710,7 @@ public final class AudioAttributes implements Parcelable {
          * @return the same Builder instance.
          */
         public Builder setFlags(int flags) {
-            flags &= AudioAttributes.FLAG_ALL;
+            flags &= AudioAttributes.FLAG_ALL_PUBLIC;
             mFlags |= flags;
             return this;
         }