ASoC: fsl: eukrea-tlv320: Delete unneeded test before of_node_put

of_node_put() supports NULL as its argument, so the initial test is not
necessary.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>