If cs35l35->pdata.stereo is false then "ret" isn't initialized.

Fixes: 6387f866 ("ASoC: Add support for Cirrus Logic CS35L35 Amplifier")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NPaul Handrigan <Paul.Handrigan@cirrus.com>
Signed-off-by: NMark Brown <broonie@kernel.org>