regulator: tps6594: Fix device node reference leaks in multiphase loop

In the Linux kernel, the following vulnerability has been resolved: regulator: tps6594: Fix device node reference leaks in multiphase loop In tps6594_regulator_probe(), the multi-phase configuration loop calls of_find_node_by_name() to find buck nodes by name, and of_get_parent() twice to navigate to the PMIC parent node. None of the acquired node references (np, intermediate parent, np_pmic_parent) are ever released via of_node_put(), causing a reference leak on every loop iteration. Additionally, of_find_node_by_name() can return NULL, but the result was immediately passed to of_node_full_name() and of_get_parent() without a NULL check, which could lead to a NULL pointer dereference. Fix this by: - Adding a NULL check for np after of_find_node_by_name() - Storing the intermediate parent node in a local variable np_parent - Calling of_node_put() on np, np_parent and np_pmic_parent at the end of each loop iteration