gpio_chip.can_sleep is 0, but current code uses mutex in pch_gpio_set
pch_gpio_get and pch_gpio_direction_input functions.
Thus those functions are not callable from interrupt context.
This patch converts mutex into spinlock.
Signed-off-by: NAxel Lin <axel.lin@gmail.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>