ASoC: AMD: Always stop ch2 first

Commit 6b116dfb ("ASoC: AMD: make channel 1 dma as circular") made
both channels circular, so this comment and logic no longer applies.  Always
stop ch2 (the channel closest to the output) before ch1.  This ensures
that the downstream circular DMA channel does not continue to play/capture
repeated samples after the upstream circular DMA channel has already
stopped.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>