pinctrl: renesas: rzg2l: Fix missing port register 21h

Remove the duplicate port register 22h and replace it with missing port
register 21h.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20210922074140.22178-1-biju.das.jz@bp.renesas.com
Fixes: c4c4637e

 ("pinctrl: renesas: Add RZ/G2L pin and gpio controller driver")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>