Driver for PCengines APUv2 board's front LEDs and Button,
which are attached to AMD PCH GPIOs. Due to lack of dedicated
ACPI entry, detecting the board via DMI.

Cc: linux-gpio@vger.kernel.org
Cc: linus.walleij@linaro.org
Cc: bgolaszewski@baylibre.com
Cc: dvhart@infradead.org
Cc: platform-driver-x86@vger.kernel.org
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NEnrico Weigelt, metux IT consult <info@metux.net>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>