Add the function defined in gpio.h to translate a gpio_t into a value for use in an ACPI GPIO pin table. For skylake this just returns the gpio_t value as the pins are translated directly and they are all in the same ACPI device. Change-Id: I00fad1cafec2f2d63dce9f7779063be0532649c7 Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Reviewed-on: https://review.coreboot.org/15520 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org>