clk: qoriq: fix refcount leak in clockgen_init()

The of_find_compatible_node() returns a node pointer with refcount
incremented, but there is the lack of use of the of_node_put() when
done. Add the missing of_node_put() to release the refcount.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Fixes: 0dfc86b3 ("clk: qoriq: Move chip-specific knowledge into driver")
Signed-off-by: Stephen Boyd <sboyd@kernel.org>