pinctrl: renesas: r8a77951: 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/100605798d02cbd8695aedfaaaa8a3b63e3a281f.1640269757.git.geert+renesas@glider.be