pinctrl: mediatek: correct debounce time unit in mtk_gpio_set_debounce

pinctrl: mediatek: correct debounce time unit in mtk_gpio_set_debounce

commit 5fedbb923936174ab4d1d5cc92bca1cf6b2e0ca2 upstream.

The debounce time unit for gpio_chip.set_debounce is us but
mtk_gpio_set_debounce regard it as ms.
Fix this by correct debounce time array dbnc_arr so it can find correct
debounce setting. Debounce time for first debounce setting is 500us,
correct this as well.

While I'm at it, also change the debounce time array name to
"debounce_time" for readability.

Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Hongzhou Yang <hongzhou.yang@mediatek.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>