[IA64] SN2 needs platform specific irq_to_vector() function.

Add base support for implementing platform_irq_to_vector(), and
then use it on SN2.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: John Keller <jpk@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/include/asm-ia64/hw_irq.h b/include/asm-ia64/hw_irq.h
index efa1b8f..bba5baa 100644
--- a/include/asm-ia64/hw_irq.h
+++ b/include/asm-ia64/hw_irq.h
@@ -124,6 +124,11 @@
 extern irq_desc_t irq_desc[NR_IRQS];
 
 #ifndef CONFIG_IA64_GENERIC
+static inline ia64_vector __ia64_irq_to_vector(int irq)
+{
+	return irq_cfg[irq].vector;
+}
+
 static inline unsigned int
 __ia64_local_vector_to_irq (ia64_vector vec)
 {
@@ -145,7 +150,7 @@
 static inline ia64_vector
 irq_to_vector (int irq)
 {
-	return irq_cfg[irq].vector;
+	return platform_irq_to_vector(irq);
 }
 
 /*