drivers: gpio: mcux_lpc: Convert driver to use devicetree port prop

Move to using port property for a few cases in which we need to know
which specific hardware port a device is for.  This allows us to
remove the PORT0/1 Kconfig options.  This also fixes the issue that
assumed pio0 would map to DT_INST(0) and pio1 would map to DT_INST(1)

Fixes #35693

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>