pinctrl: renesas: r8a77965: Add R8A774B1 PFC support

Renesas RZ/G2N (r8a774b1) is pin compatible with R-Car M3-N (r8a77965),
however it doesn't have several automotive specific peripherals. Add
a r8a77965 specific pin groups/functions along with common pin
groups/functions for supporting both r8a77965 and r8a774b1 SoC.

PFC changes are synced from mainline linux-5.9 commit
bbf5c979011a ("Linux 5.9").

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>