Up to now cs35l41_remove() returns zero unconditionally. Make it
return void instead which makes it easier to see in the callers that
there is no error to handle.

Also the return value of i2c, platform and spi remove callbacks is
ignored anyway.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20211020132416.30288-1-u.kleine-koenig@pengutronix.deSigned-off-by: Mark Brown <broonie@kernel.org>