pinctrl: renesas: r8a7790: Share more VIN pin group data

Pin group vin2_g8 is a subset of vin2_data24.

This reduces kernel size by 64 bytes.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/a4f6a70344654456abea1f15539219d1e02a74fe.1640269757.git.geert+renesas@glider.be