ASoC: smdk_wm9713: fix resource leak in smdk_init error path

Fix the error path to properly free allocated resources.

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