ASoC: Samsung: return error if drvdata is not set

This patch fixes a possible crash in case drvdata for the secondary
device is not set.

Signed-off-by: Prathyush K <prathyush.k@samsung.com>
Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>