We added acpi_gpiochip_pin_to_gpio_offset() because there was a need to
translate from ACPI GpioIo/GpioInt number to Linux GPIO number in the
Cherryview pinctrl driver. This translation is necessary because
Cherryview has gaps in the pin list and the driver used continuous GPIO
number space in Linux side as follows:

  created GPIO range 0->7 ==> INT33FF:03 PIN 0->7
  created GPIO range 8->19 ==> INT33FF:03 PIN 15->26
  created GPIO range 20->25 ==> INT33FF:03 PIN 30->35
  created GPIO range 26->33 ==> INT33FF:03 PIN 45->52
  created GPIO range 34->43 ==> INT33FF:03 PIN 60->69
  created GPIO range 44->54 ==> INT33FF:03 PIN 75->85

For example when ACPI GpioInt resource refers to GPIO 81 (SDMMC3_CD_B)
we translate from pin 81 to the corresponding Linux GPIO number, which
is 50. This number is then used when the GPIO is accessed through gpiolib.

It turns out, this is not necessary at all. We can just pass 1:1 mapping
between Linux GPIO numbers and pin numbers (including gaps) and the
pinctrl core handles all the details automatically:

  created GPIO range 0->7 ==> INT33FF:03 PIN 0->7
  created GPIO range 15->26 ==> INT33FF:03 PIN 15->26
  created GPIO range 30->35 ==> INT33FF:03 PIN 30->35
  created GPIO range 45->52 ==> INT33FF:03 PIN 45->52
  created GPIO range 60->69 ==> INT33FF:03 PIN 60->69
  created GPIO range 75->85 ==> INT33FF:03 PIN 75->85

Here GPIO 81 is exactly same than the hardware pin 81 (SDMMC3_CD_B).

As an added bonus this simplifies both the ACPI GPIO core code and the
Cherryview pinctrl driver.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>