pinctrl: equilibrium: Fix device node reference leak in pinbank_init()

pinctrl: equilibrium: Fix device node reference leak in pinbank_init()

When calling of_parse_phandle_with_fixed_args(), the caller is
responsible to call of_node_put() to release the reference of device
node.

In pinbank_init(), the reference of the node obtained from the
"gpio-ranges" property is never released, resulting in a reference
count leak.

Add the missing of_node_put() call to fix the leak.

Fixes: 1948d5c51dba ("pinctrl: Add pinmux & GPIO controller driver for a new SoC")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>