pinctrl: at91-pio4: use proper format specifier for unsigned int

Use %u instead of %d as line is unsigned int.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20230302110116.342486-5-claudiu.beznea@microchip.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>