gpio: dwapb: Move MFD-specific IRQ handler

For better readability let's group all the IRQ handlers in a single place
of the driver instead of having them scatter around all over the file.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200730152808.2955-4-Sergey.Semin@baikalelectronics.ruSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-dwapb.c

@@ -220,6 +220,11 @@ static void dwapb_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
+static irqreturn_t dwapb_irq_handler_mfd(int irq, void *dev_id)
+{
+	return IRQ_RETVAL(dwapb_do_irq(dev_id));
+}
+
 static void dwapb_irq_enable(struct irq_data *d)
 {
 	struct irq_chip_generic *igc = irq_data_get_irq_chip_data(d);
@@ -349,11 +354,6 @@ static int dwapb_gpio_set_config(struct gpio_chip *gc, unsigned offset,
 	return dwapb_gpio_set_debounce(gc, offset, debounce);
 }
 
-static irqreturn_t dwapb_irq_handler_mfd(int irq, void *dev_id)
-{
-	return IRQ_RETVAL(dwapb_do_irq(dev_id));
-}
-
 static void dwapb_configure_irqs(struct dwapb_gpio *gpio,
 				 struct dwapb_gpio_port *port,
 				 struct dwapb_port_property *pp)