High-frequency files increasingly use a block size of over 4608B, which
means we need larger buffers to decode them. However, larger buffers no
longer fit in IRAM on less-capable devices, hurting performance for
"normal" file playback.
On our slowest devices (M68K and PP-based devices), this is not worth
the tradeoff as they will likely not have enough CPU oomph to decode and
downmix these files in realtime.
S5L87xx-based devices have the raw performance to do this, so we decided
to err on the side of wider file compatibility at the cost of some
performance.
All other devices are unaffected.
Change-Id: I7344cf4c8c6b7b5c14f1ea67381160665d6ece5b
