Blackfin arch: Finalize the generic gpio support - add gpio_to_irq and irq_to_gpio

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

diff --git a/include/asm-blackfin/mach-bf537/irq.h b/include/asm-blackfin/mach-bf537/irq.h
index 8af2a83..36c44bc 100644
--- a/include/asm-blackfin/mach-bf537/irq.h
+++ b/include/asm-blackfin/mach-bf537/irq.h
@@ -160,6 +160,8 @@
 #define IRQ_PH14        96
 #define IRQ_PH15        97
 
+#define GPIO_IRQ_BASE	IRQ_PF0
+
 #ifdef CONFIG_IRQCHIP_DEMUX_GPIO
 #define NR_IRQS     (IRQ_PH15+1)
 #else