pinctrl: renesas: rza2: Add lock around pinctrl_generic{{add,remove}_group,{add,remove}_function}

[ Upstream commit 8fcc1c40 ]

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.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Sasha Levin <sashal@kernel.org>