ASoC: imx-sgtl5000: put of nodes if finding codec fails

Make sure to properly put the of node in case finding the codec
fails.

Fixes: 81e8e492 ("ASoC: fsl: add sgtl5000 clock support for imx-sgtl5000")
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>