ASoC: cs35l35: returning uninitialized in probe()

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

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