gpio: rcar: Pedantic formatting

A tab sneaked in, where it shouldn't be.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>