ARM: pxa: rename gpio_to_irq and irq_to_gpio

Avoid to define gpio_to_irq() and irq_to_gpio() for potential name
confliction since multiple architecture will be built together.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
diff --git a/arch/arm/mach-pxa/z2.c b/arch/arm/mach-pxa/z2.c
index ead32c9..4246618 100644
--- a/arch/arm/mach-pxa/z2.c
+++ b/arch/arm/mach-pxa/z2.c
@@ -573,7 +573,7 @@
 	.modalias		= "libertas_spi",
 	.platform_data		= &z2_lbs_pdata,
 	.controller_data	= &z2_lbs_chip_info,
-	.irq			= gpio_to_irq(GPIO36_ZIPITZ2_WIFI_IRQ),
+	.irq			= PXA_GPIO_TO_IRQ(GPIO36_ZIPITZ2_WIFI_IRQ),
 	.max_speed_hz		= 13000000,
 	.bus_num		= 1,
 	.chip_select		= 0,