extcon: gpio: Use gpio driver/chip debounce if supported

This patch use gpio_set_debounce() API provided from gpiolib if SoC or device
driver with gpio support gpio_set_debounce() function.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>