cpufreq: imx6q: fix error handling

When speed checking failed, direclty jumping to put_node label
is not correct. Need jump to out_free_opp to avoid resources leak.

Fixes: 2733fb0d ("cpufreq: imx6q: read OCOTP through nvmem for imx6ul/imx6ull")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>