cpufreq: s5pv210: fix refcount leak

cpufreq: s5pv210: fix refcount leak

In function `s5pv210_cpu_init`, a possible refcount inconsistency has
been identified, causing a resource leak.

Why it is a bug:
1. For every clk_get, there should be a matching clk_put on every
successive error handling path.
2. After calling `clk_get(dmc1_clk)`, variable `dmc1_clk` will not be
freed even if any error happens.

How it is fixed: For every failed path, an extra goto label is added to
ensure `dmc1_clk` will be freed regardlessly.

Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>