Fix to return a negative error code from the clk_get() error handling
case instead of 0, as done elsewhere in this function.

Fixes: 343a8d17 (cpufreq: scpi: remove arm_big_little dependency)
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Acked-by: NSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>