Input: twl6040-vibra - fix DT node memory management

BugLink: http://bugs.launchpad.net/bugs/1754375

commit c52c545e upstream.

commit e7ec014a ("Input: twl6040-vibra - update for device tree support")

made the separate vibra DT node to a subnode of the twl6040.

It now calls of_find_node_by_name() to locate the "vibra" subnode.
This function has a side effect to call of_node_put on() for the twl6040
parent node passed in as a parameter. This causes trouble later on.

Solution: we must call of_node_get() before of_find_node_by_name()
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/input/misc/twl6040-vibra.c

@@ -262,6 +262,7 @@ static int twl6040_vibra_probe(struct platform_device *pdev)
 	int vddvibr_uV = 0;
 	int error;
 
+	of_node_get(twl6040_core_dev->of_node);
 	twl6040_core_node = of_find_node_by_name(twl6040_core_dev->of_node,
 						 "vibra");
 	if (!twl6040_core_node) {