mfd: wcd934x: Fix an error handling path in wcd934x_slim_probe()

mfd: wcd934x: Fix an error handling path in wcd934x_slim_probe()

If devm_gpiod_get_optional() fails, some resources need to be released, as
already done in the .remove() function.

While at it, remove the unneeded error code from a dev_err_probe() call.
It is already added in a human readable way by dev_err_probe() itself.

Fixes: 6a0ee2a61a31 ("mfd: wcd934x: Replace legacy gpio interface for gpiod")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/02d8447f6d1df52cc8357aae698152e9a9be67c6.1684565021.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Lee Jones <lee@kernel.org>