logic_pio: Constify fwnode_handle

The fwnode_handle passed into find_io_range_by_fwnode() and
logic_pio_trans_hwaddr() are not modified, so make them const.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20241010-dt-const-v1-2-87a51f558425@kernel.org


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>