sparc: Implement irq_of_parse_and_map() and irq_dispose_mapping().

This allows more OF layer code to be shared between powerpc and
sparc.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/include/asm/prom.h b/arch/sparc/include/asm/prom.h
index b5efc4d..58b85fa 100644
--- a/arch/sparc/include/asm/prom.h
+++ b/arch/sparc/include/asm/prom.h
@@ -96,6 +96,14 @@
 {
 }
 
+/* These routines are here to provide compatibility with how powerpc
+ * handles IRQ mapping for OF device nodes.  We precompute and permanently
+ * register them in the of_device objects, whereas powerpc computes them
+ * on request.
+ */
+extern int irq_of_parse_and_map(struct device_node *node, int index);
+#define irq_dispose_mapping(irq) do { } while (0)
+
 /*
  * NB:  This is here while we transition from using asm/prom.h
  * to linux/of.h