[ARM] pxa: add missing IRQ_PXA910_NONE to irqs.h

Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/arch/arm/mach-mmp/include/mach/irqs.h b/arch/arm/mach-mmp/include/mach/irqs.h
index e83e45e..16295cf 100644
--- a/arch/arm/mach-mmp/include/mach/irqs.h
+++ b/arch/arm/mach-mmp/include/mach/irqs.h
@@ -52,6 +52,7 @@
 /*
  * Interrupt numbers for PXA910
  */
+#define IRQ_PXA910_NONE			(-1)
 #define IRQ_PXA910_AIRQ			0
 #define IRQ_PXA910_SSP3			1
 #define IRQ_PXA910_SSP2			2