[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/machvec_init.h b/include/asm-ia64/machvec_init.h
index 2d36f68..7f21249 100644
--- a/include/asm-ia64/machvec_init.h
+++ b/include/asm-ia64/machvec_init.h
@@ -2,6 +2,7 @@
 
 extern ia64_mv_send_ipi_t ia64_send_ipi;
 extern ia64_mv_global_tlb_purge_t ia64_global_tlb_purge;
+extern ia64_mv_irq_to_vector __ia64_irq_to_vector;
 extern ia64_mv_local_vector_to_irq __ia64_local_vector_to_irq;
 extern ia64_mv_pci_get_legacy_mem_t ia64_pci_get_legacy_mem;
 extern ia64_mv_pci_legacy_read_t ia64_pci_legacy_read;