OF: Add helper for matching against linux,stdout-path

devicetrees may have a linux,stdout-path property in the chosen
node describing the console device. This adds a helper function
to match a device against this property so a driver can call
add_preferred_console for a matching device.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/of.h b/include/linux/of.h
index 1fd08ca..429e168 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -343,6 +343,8 @@
 		s;						\
 		s = of_prop_next_string(prop, s))
 
+int of_device_is_stdout_path(struct device_node *dn);
+
 #else /* CONFIG_OF */
 
 static inline const char* of_node_full_name(struct device_node *np)
@@ -505,6 +507,11 @@
 	return 0;
 }
 
+static inline int of_device_is_stdout_path(struct device_node *dn)
+{
+	return 0;
+}
+
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
 #define of_property_for_each_u32(np, propname, prop, p, u) \