SpatialAudio: Init codec and buffer size from startStream()

startStream(false):  1) change buffer size 2) do nothing if codec isn't LC3; change codec if codec is LC3
startStream(true): 1) change buffer size 2) do nothing if codec is LC3; change codec if codec isn't LC3
setLatencyMode(true/false): only change buffer size.

Bug: 214615268
Test: build
Tag: #feature
Change-Id: Ia9e6cf10052d78200cea5da468d6880bc676e8fa