pinctrl: renesas: Initial R8A779A0 (V3U) PFC support

This patch adds initial pinctrl support for the R8A779A0 (V3U) SoC,
including bias, drive strength and voltage control.

Based on patch by LUU HOAI <hoai.luu.ub@renesas.com>.

Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210112165912.30876-5-uli+renesas@fpond.eu


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>