pinctrl: renesas: rzg2l: Add validation of GPIO pin in rzg2l_gpio_request()

Validate the GPIO pin request in the rzg2l_gpio_request() callback using
the rzg2l_validate_gpio_pin() function.  This stops any accidental usage
of GPIO pins which are not supported by the SoC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20230925154548.27048-1-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>