pinctrl: rza1: Fix flag name in comment

rza1_swio_pin relates to the swio flag instead of the bidir flag.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Link: https://lore.kernel.org/r/20200507074516.29903-1-geert+renesas@glider.be