pinctrl: renesas: r8a779f0: Add I2C pins, groups, and functions

Add pins, groups, and functions for the I2C Bus Interfaces (I2C) on the
Renesas R-Car S4-8 (R8A779F0) SoC.

Extracted from a larger patch in the BSP by LUU HOAI.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/217f5b3e3888b5899c375d3cb1ec8780f6a9e19b.1645457792.git.geert+renesas@glider.be