Some GPIO controller drivers request sleepable context and so can't
be accessed from IRQ context. Using gpiod_set/get_value accessors
with such controller leads to a kernel warning since they are
reserved for atomic context (according to the documentation).

Use the postfixed _cansleep version instead, indicating that context
is safe for sleeping if necessary. Note that this is the case here
since we never toggle the gpio neither from IRQ nor from a spinlocked
section.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>