On the SIMATIC, IOT2040 only a single pin is exportable as GPIO, the
rest is required to operate the UART. To allow modeling this case,
expand the platform device data structure to specify a (consecutive) pin
subset for exporting by the gpio-exar driver.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>