The pinctrl group and function creation/remove calls expect
caller to take care of locking. Add lock around these functions.

Fixes: b59d0e78 ("pinctrl: Add RZ/A2 pin and gpio controller")
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20230815131558.33787-4-biju.das.jz@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>