devicetree: add helper inline for retrieving a node's full name

The pattern (np ? np->full_name : "<none>") is rather common in the
kernel, but can also make for quite long lines.  This patch adds a new
inline function, of_node_full_name() so that the test for a valid node
pointer doesn't need to be open coded at all call sites.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rob Herring <rob.herring@calxeda.com>
diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 9cf0060..ff8ab7b 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -255,7 +255,7 @@
 
 	skiplevel:
 		/* Iterate again with new parent */
-		pr_debug(" -> new parent: %s\n", newpar ? newpar->full_name : "<>");
+		pr_debug(" -> new parent: %s\n", of_node_full_name(newpar));
 		of_node_put(ipar);
 		ipar = newpar;
 		newpar = NULL;