ASoC: alc5632: fix uninit var in alc5632_probe()

alc5632_probe() returns ret, yet it is not initialized or set anywhere.
This ends up causing the function to appear to fail, and audio not to
work on the Toshiba AC100, with my compiler at least.

This function used to set ret in all cases, but recent cleanup removed
that.

Fixes: 5d6be5aa6bec ("ASoC: codec: Simplify ASoC probe code.")
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>