ASoC: fsl: imx-wm8962: Fix error path

If the 'failed to find codec platform device' error path is executed, it should
jump to 'fail' label instead of returning an error immediately.

'fail' label will then free the ssi_np and codec_np previously acquired nodes.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>