pinctrl: renesas: r8a7796: Share more VIN pin group data

Pin group vin4_g8 is a subset of vin4_data24_a.
Pin group vin5_high8 is a subset of vin5_data16.

This reduces kernel size by 128 bytes.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/1fc04bb08e2c26109509bd53b19ffbf9ce83d2f1.1640269757.git.geert+renesas@glider.be