pwm: ab8500: Fix error code in probe()

This code accidentally return positive EINVAL instead of negative
-EINVAL.

Fixes: eb41f334 ("pwm: ab8500: Fix register offset calculation to not depend on probe order")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-ab8500.c

@@ -190,7 +190,7 @@ static int ab8500_pwm_probe(struct platform_device *pdev)
 	int err;
 
 	if (pdev->id < 1 || pdev->id > 31)
-		return dev_err_probe(&pdev->dev, EINVAL, "Invalid device id %d\n", pdev->id);
+		return dev_err_probe(&pdev->dev, -EINVAL, "Invalid device id %d\n", pdev->id);
 
 	/*
 	 * Nothing to be done in probe, this is required to get the