gpio: Use irq_desc_get_xxx() to avoid redundant lookup of irq_desc

Use irq_desc_get_xxx() to avoid redundant lookup of irq_desc while we
already have a pointer to corresponding irq_desc.

Preparatory patch for the removal of the 'irq' argument from irq flow
handlers.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/gpio/gpio-timberdale.c b/drivers/gpio/gpio-timberdale.c
index fd1970e..ac53ff0 100644
--- a/drivers/gpio/gpio-timberdale.c
+++ b/drivers/gpio/gpio-timberdale.c
@@ -194,11 +194,12 @@
 
 static void timbgpio_irq(unsigned int irq, struct irq_desc *desc)
 {
-	struct timbgpio *tgpio = irq_get_handler_data(irq);
+	struct timbgpio *tgpio = irq_desc_get_handler_data(desc);
+	struct irq_data *data = irq_desc_get_irq_data(desc);
 	unsigned long ipr;
 	int offset;
 
-	desc->irq_data.chip->irq_ack(irq_get_irq_data(irq));
+	data->chip->irq_ack(data);
 	ipr = ioread32(tgpio->membase + TGPIO_IPR);
 	iowrite32(ipr, tgpio->membase + TGPIO_ICR);