gpio: dwapb: Switch to more usual pattern of RMW in dwapb_gpio_set_debounce()

More usual pattern is to prepare value and then write it in a single place.
Switch code in dwapb_gpio_set_debounce() to it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20200415141534.31240-10-andriy.shevchenko@linux.intel.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-dwapb.c

@@ -327,9 +327,10 @@ static int dwapb_gpio_set_debounce(struct gpio_chip *gc,
 
 	val_deb = dwapb_read(gpio, GPIO_PORTA_DEBOUNCE);
 	if (debounce)
-		dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, val_deb | mask);
+		val_deb |= mask;
 	else
-		dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, val_deb & ~mask);
+		val_deb &= ~mask;
+	dwapb_write(gpio, GPIO_PORTA_DEBOUNCE, val_deb);
 
 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);