Add const value for manually set surround formats.

To make surround sound setting more clear to users, we are changing
surround setting from ALWAYS to MANUAL. With MANUAL, users could enable
surround formats according to their need.

Bug: 67479735
Test: Try creating AudioTrack with enable/disable surround formats.
Change-Id: I32c5a766300fc0ed294150f703e46602970a76d3
1 file changed