gpio: pca954x: fix undefined error code from remove

The recent addition of the regulator support has led to the pca953x_remove
function returning uninitialized data when no platform data pointer is
provided, as gcc warns when using -Wmaybe-uninitialized:

drivers/gpio/gpio-pca953x.c: In function 'pca953x_remove':
drivers/gpio/gpio-pca953x.c:860:9: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This restores the previous behavior, returning 0 on success.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: e23efa31 ("gpio: pca954x: Add vcc regulator and enable it")
Acked-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-pca953x.c

@@ -853,6 +853,8 @@ static int pca953x_remove(struct i2c_client *client)
 		if (ret < 0)
 			dev_err(&client->dev, "%s failed, %d\n",
 					"teardown", ret);
+	} else {
+		ret = 0;
 	}
 
 	regulator_disable(chip->regulator);