drivers: gpio: gpio_mcux_igpio: add workaround for non contiguous pins

some iMX RT SOCs have non contiguous sets of gpio pins available, which
caused issues when selecting appropriate pinmux for these parts. Add
workaround code to adjust offset of pinmux settings when configuring
these pins.

Fixes #44391

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>