of/sparc: move is_root_node() to of.h

Rename is_root_node() to of_node_is_root() and make it available for
all archs to use, as it's not PROM-specific.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/linux/of.h b/include/linux/of.h
index a367e19..b0756f3 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -70,6 +70,11 @@
 extern struct device_node *of_chosen;
 extern rwlock_t devtree_lock;
 
+static inline bool of_node_is_root(const struct device_node *node)
+{
+	return node && (node->parent == NULL);
+}
+
 static inline int of_node_check_flag(struct device_node *n, unsigned long flag)
 {
 	return test_bit(flag, &n->_flags);