pinctrl: renesas: rzt2h: Remove unused variable in rzt2h_pinctrl_register()

pinctrl: renesas: rzt2h: Remove unused variable in rzt2h_pinctrl_register()

Variable 'j' in rzt2h_pinctrl_register() is incremented during pin
descriptor initialization but never used afterwards.

Remove the unused variable and the associated dead code.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260513115312.1574367-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>