pinctrl: renesas: rzg2l: Remove OEN ops for RZ/G3E

The RZ/G3E pin controller does not advertise PIN_CFG_OEN capability, so
there is no valid mapping for output-enable bits on this SoC. Remove the
oen_read and oen_write callbacks from the RZ/G3E driver data to defer
OEN support until PIN_CFG_OEN support is added.

This is a preparatory change for future unification of OEN handling across
the driver.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20250806195555.1372317-5-prabhakar.mahadev-lad.rj@bp.renesas.com


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