pinctrl: sh-pfc: r8a7796: Remove placeholder I2C pin data

Pin data for I2C controllers 0, 3 and 5 is properly defined already.

Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>