cpuidle: dt: Add missing 'of_node_put()'

'of_node_put()' should be called on pointer returned by
'of_parse_phandle()' when done. In this function this is done in all path
except this 'continue', so add it.

Fixes: 97735da0

 (drivers: cpuidle: Add status property to ARM idle states)
Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>