pinctrl: renesas: rzg2l: Fix save/restore of {IOLH,IEN,PUPD,SMT} registers

pinctrl: renesas: rzg2l: Fix save/restore of {IOLH,IEN,PUPD,SMT} registers

The rzg2l_pinctrl_pm_setup_regs() handles save/restore of
{IOLH,IEN,PUPD,SMT} registers during s2ram, but only for ports where all
pins share the same pincfg. Extend the code to also support ports with
variable pincfg per pin, so that {IOLH,IEN,PUPD,SMT} registers are
correctly saved and restored for all pins.

Fixes: 254203f9a94c ("pinctrl: renesas: rzg2l: Add suspend/resume support")
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260326162459.101414-1-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>