ASoC: Clean up the CODEC device as well as the board for SMDK WM9713

Otherwise we try to re-register the CODEC device if the module is reloaded
and sysfs becomes miserable.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassi.brar@samsung.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>