docs/zh_CN: Remove IRQ and oops-tracing

The English version of IRQ has been refactored and
the new document (not called that anymore) has been
moved to core-api/irq, which has been translated
into Chinese. oops-tracing is pretty much the same,
let's remove them.

Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
Reviewed-by: Wu XiangCheng <bobwxc@email.cn>
Link: https://lore.kernel.org/r/7dc43c33ea7e2edf668070b203dce83b285f2cdb.1661431365.git.siyanteng@loongson.cn


Signed-off-by: Jonathan Corbet <corbet@lwn.net>