clk: qoriq: Hold reference returned by of_get_parent()

clk: qoriq: Hold reference returned by of_get_parent()

In legacy_init_clockgen(), we need to hold the reference returned
by of_get_parent() and use it to call of_node_put() for refcount
balance.

Beside, in create_sysclk(), we need to call of_node_put() on 'sysclk'
also for refcount balance.

Fixes: 0dfc86b3173f ("clk: qoriq: Move chip-specific knowledge into driver")
Signed-off-by: Liang He <windhl@126.com>
Link: https://lore.kernel.org/r/20220628143851.171299-1-windhl@126.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>