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-mmp/flint.c b/arch/arm/mach-mmp/flint.c
index c4fd806..a64c172 100644
--- a/arch/arm/mach-mmp/flint.c
+++ b/arch/arm/mach-mmp/flint.c
@@ -87,8 +87,8 @@
 		.flags  = IORESOURCE_MEM,
 	},
 	[1] = {
-		.start  = gpio_to_irq(155),
-		.end    = gpio_to_irq(155),
+		.start  = MMP_GPIO_TO_IRQ(155),
+		.end    = MMP_GPIO_TO_IRQ(155),
 		.flags  = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHEDGE,
 	}
 };