ASoC: fsl_spdif: Make error message concise

Currently the error message uses 'np->full_name' which leads to a very verbose
log that contains the full path of the node.

We can have a concise log by using pdev->name instead.

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