ASoC: wm8961: fix resource reclaim in wm8961_register error path

This patch fixes the error path in wm8961_register to properly free resources.

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