clk: keystone: syscon-clk: Use dev_err_probe() helper

dev_err() can be replace with dev_err_probe() which will check if error
code is -EPROBE_DEFER.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220913031956.984475-1-yangyingliang@huawei.com


Signed-off-by: Stephen Boyd <sboyd@kernel.org>