MIPS: RB532: provide GPIO_BUILTIN_NR and irq_to_gpio/gpio_to_irq

This patchs defines the number of built-in the GPIOs present
on the SoC as Documentation/gpio.txt recommends to do.
Define irq_to_gpio/gpio_to_irq to return the right values so that
it fixes a compilation error on drivers/gpio/gpiolib.c
when enabling debugfs.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-rc32434/gpio.h

@@ -14,16 +14,16 @@
 #define _RC32434_GPIO_H_
 
 #include <linux/types.h>
+#include <asm-generic/gpio.h>
+
+#define NR_BUILTIN_GPIO		32
 
 #define gpio_get_value	__gpio_get_value
 #define gpio_set_value	__gpio_set_value
-
 #define gpio_cansleep	__gpio_cansleep
 
-#define gpio_to_irq(gpio)	IRQ_GPIO(gpio)
-#define irq_to_gpio(irq)	IRQ_TO_GPIO(irq)
-
-#include <asm-generic/gpio.h>
+#define gpio_to_irq(gpio)	(8 + 4 * 32 + gpio)
+#define irq_to_gpio(irq)	(irq - (8 + 4 * 32))
 
 struct rb532_gpio_reg {
 	u32   gpiofunc;   /* GPIO Function Register