pinctrl: unbreak error messages

It's better to not line break error messages to allow easier grepping
for them even when the line gets >80 chars. Additionally some minor
reformating is done.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>