pinctrl: renesas: r8a77470: Share MMC pin group data

Pin groups mmc_data[14] and sdhi1_data[14] are subsets of mmc_data8.
Pin group sdhi1_ctrl can be an alias for mmc_ctrl.

This reduces kernel size by 96 bytes.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/e3d19e19f7666dbcefeec351a5096a86348404ae.1640269757.git.geert+renesas@glider.be