docs/zh_CN: Add opp Chinese translation

Translate power/opp.rst into Chinese.
Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Reviewed-by: Alex Shi <alexs@kernel.org>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20211229024212.32752-4-tangyizhou@huawei.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/translations/zh_CN/power/index.rst

@@ -14,6 +14,8 @@
 .. toctree::
     :maxdepth: 1
 
+    opp
+
 TODOList:
 
     * apm-acpi
@@ -22,7 +24,6 @@ TODOList:
     * drivers-testing
     * energy-model
     * freezing-of-tasks
-    * opp
     * pci
     * pm_qos_interface
     * power_supply_class