ASoC: wm8994: playback => capture

Sparse caught that initialize "playback" two times instead of
initializing "capture".

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>