powerpc: Look for "stdout-path" when setting up legacy consoles

Commit 78e5dfea ("powerpc: dts: replace 'linux,stdout-path' with
'stdout-path'") broke the default console on a number of embedded
PowerPC systems, because it failed to also update the code in
arch/powerpc/kernel/legacy_serial.c to look for that property in
addition to the old one.

This fixes it.

Fixes: 78e5dfea ("powerpc: dts: replace 'linux,stdout-path' with 'stdout-path'")
Cc: stable@vger.kernel.org # v4.17+
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/legacy_serial.c

@@ -372,6 +372,8 @@ void __init find_legacy_serial_ports(void)
 
 	/* Now find out if one of these is out firmware console */
 	path = of_get_property(of_chosen, "linux,stdout-path", NULL);
+	if (path == NULL)
+		path = of_get_property(of_chosen, "stdout-path", NULL);
 	if (path != NULL) {
 		stdout = of_find_node_by_path(path);
 		if (stdout)
@@ -595,8 +597,10 @@ static int __init check_legacy_serial_console(void)
 	/* We are getting a weird phandle from OF ... */
 	/* ... So use the full path instead */
 	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
+	if (name == NULL)
+		name = of_get_property(of_chosen, "stdout-path", NULL);
 	if (name == NULL) {
-		DBG(" no linux,stdout-path !\n");
+		DBG(" no stdout-path !\n");
 		return -ENODEV;
 	}
 	prom_stdout = of_find_node_by_path(name);