AudioAttributes: always build formatted tags from tag array

An AudioAttributes instance can either be built through the
 Builder, or from unmarshalling: the mFormattedTags field
 should always be in sync with the array of tags.
In toString() method, use the more compact mFormattedTags.

Change-Id: Ie06cd7758bf4f2d2693fedaa8c3ba4245802d921
1 file changed