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-bf548/irq.h b/include/asm-blackfin/mach-bf548/irq.h
index e548d3c..21f06f7 100644
--- a/include/asm-blackfin/mach-bf548/irq.h
+++ b/include/asm-blackfin/mach-bf548/irq.h
@@ -337,6 +337,8 @@
 #define IRQ_PJ14	BFIN_PJ_IRQ(14)		/* N/A */
 #define IRQ_PJ15	BFIN_PJ_IRQ(15)		/* N/A */
 
+#define GPIO_IRQ_BASE	IRQ_PA0
+
 #ifdef CONFIG_IRQCHIP_DEMUX_GPIO
 #define NR_IRQS     (IRQ_PJ15+1)
 #else