ARM: gpio: consolidate gpio_to_irq

Many of the gpio_to_irq implementations use the gpiolib version of this
function.  Provide the standard gpiolib gpio_to_irq() for everyone, but
allow platforms to override it if they wish.  Add the neccessary
overrides for those platforms which do not use the standard definition.

Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/gpio.h b/arch/arm/include/asm/gpio.h
index 15e8970..5032224 100644
--- a/arch/arm/include/asm/gpio.h
+++ b/arch/arm/include/asm/gpio.h
@@ -14,4 +14,13 @@
 #define gpio_cansleep   __gpio_cansleep
 #endif
 
+/*
+ * Provide a default gpio_to_irq() which should satisfy every case.
+ * However, some platforms want to do this differently, so allow them
+ * to override it.
+ */
+#ifndef gpio_to_irq
+#define gpio_to_irq	__gpio_to_irq
+#endif
+
 #endif /* _ARCH_ARM_GPIO_H */