Because clk_disable_unprepare() already checked NULL clock parameter,
so the additional check is unnecessary, just remove it.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Link: https://lore.kernel.org/r/20201218094647.1386-1-vulab@iscas.ac.cnSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>