[ARM] S3C24XX: Add gpio_to_irq() facility

Add gpio_to_irq() by re-directing the call to the
generic __gpio_to_irq() code in the gpiolib.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

arch/arm/mach-s3c2410/include/mach/gpio.h

@@ -14,6 +14,7 @@
 #define gpio_get_value	__gpio_get_value
 #define gpio_set_value	__gpio_set_value
 #define gpio_cansleep	__gpio_cansleep
+#define gpio_to_irq	__gpio_to_irq
 
 /* some boards require extra gpio capacity to support external
  * devices that need GPIO.