ALSA: ASoC: Fix WM9713 voice PCM slave mode configuration

Reported-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>