pinctrl: sh-pfc: 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.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Link: https://lore.kernel.org/r/1568881036-4404-9-git-send-email-biju.das@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>