dt-bindings: pinctrl: renesas,pfc: Document r8a779g0 support

Document Pin Function Controller (PFC) support for the Renesas R-Car V4H
(R8A779G0) SoC.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87fsjlty13.wl-kuninori.morimoto.gx@renesas.com


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