gpiolib: acpi: Switch to cansleep version of GPIO library call

The commit ca876c74

  ("gpiolib-acpi: make sure we trigger edge events at least once on boot")

added a initial value check for pin which is about to be locked as IRQ.
Unfortunately, not all GPIO drivers can do that atomically. Thus,
switch to cansleep version of the call. Otherwise we have a warning:

...
  WARNING: CPU: 2 PID: 1408 at drivers/gpio/gpiolib.c:2883 gpiod_get_value+0x46/0x50
...
  RIP: 0010:gpiod_get_value+0x46/0x50
...

The change tested on Intel Broxton with Whiskey Cove PMIC GPIO controller.

Fixes: ca876c74

 ("gpiolib-acpi: make sure we trigger edge events at least once on boot")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>