Add device driver for APU2/APU3 GPIOs

Changes v2:
- Update SPDX short identifier
- Remove gpio-keys-polled device moved to arch/x86/platform
- Fix styling
- Use spinnlock only there where it is useful
- Removed useless output on driver load
- Do bit manipulation later not on IO
- Add additional GPIOs handling mpci2_reset and mpcie3_reset.
- Add name to GPIOs exported via sysfs

Changes v3:
- Add a new platform device for the frontpanel push button.
- Get global variables from the heap
- Fix errors/warnings generated by ./scripts/checkpatch.pl

Changes v4:
gpio-apu.c
- Move bit shifting out of spinnlock
- Change declaration of int to unsigned int
- Remove redundant blank line
- Use dmi table callback
- Remove noise
pcengines-apu-platform.c
- Move platform device to drivers/platform/x86
- Remove needless include
- Add dmi information so that this device is only present on APU2 APU3 boards from PC Engines

Changes v5:
gpio-apu.c
- Remove GPIO_GENERIC select from Kconfig
- Make gpio_chip real member of apu_gpio_pdata
- Use BIT macro for get_data and get_dir functions
- Pass platform data to devm_gpiochip_add_data to get data per-instance state container
- Remove DEVNAME define
- Remove platfrom_device member from apu_gpio_pdata this
- Clean up init function
- Remove MODULE_ALIAS

Until now it was not possible to get more information to detect the MMIO_BASE address from the ACPI subsystem.

Florian Eckert (2):
gpio: Add driver for PC Engines APU boards
platform: Add reset button device for PC Engines APU boards

 drivers/gpio/Kconfig                          |   7 +
 drivers/gpio/Makefile                         |   1 +
 drivers/gpio/gpio-apu.c                       | 288 ++++++++++++++++++++++++++
 drivers/platform/x86/Kconfig                  |  11 +
 drivers/platform/x86/Makefile                 |   1 +
 drivers/platform/x86/pcengines-apu-platform.c | 114 ++++++++++
 6 files changed, 422 insertions(+)
 create mode 100644 drivers/gpio/gpio-apu.c
 create mode 100644 drivers/platform/x86/pcengines-apu-platform.c

2.11.0