Fix build when CONFIG_W1_MASTER_GPIO=m b exporting "allnodes"

ERROR: "allnodes" [drivers/w1/masters/w1-gpio.ko] undefined!

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
[grant.likely: allnodes is too generic; rename to of_allnodes]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Ville Syrjala <syrjala@sci.fi>
diff --git a/include/linux/of.h b/include/linux/of.h
index 7337dc1..60053bd 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -88,14 +88,14 @@
 #ifdef CONFIG_OF
 
 /* Pointer for first entry in chain of all nodes. */
-extern struct device_node *allnodes;
+extern struct device_node *of_allnodes;
 extern struct device_node *of_chosen;
 extern struct device_node *of_aliases;
 extern rwlock_t devtree_lock;
 
 static inline bool of_have_populated_dt(void)
 {
-	return allnodes != NULL;
+	return of_allnodes != NULL;
 }
 
 static inline bool of_node_is_root(const struct device_node *node)