Remove useless bta_dm_authentication_complete_cback return value am:...

Remove useless bta_dm_authentication_complete_cback return value am: 33b6d6f2 am: df1b46db am: 1c21933d

Original change: https://android-review.googlesource.com/c/platform/system/bt/+/1628902

Change-Id: I804c72a8b7306522c04d8bfb53fd0e8626ecdf6f