mailmap: add entry for Tiezhu Yang

Add an entry to connect all my email addresses.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Link: https://lore.kernel.org/r/1580721045-4988-1-git-send-email-yangtiezhu@loongson.cnSigned-off-by: Jonathan Corbet <corbet@lwn.net>

.mailmap

@@ -250,6 +250,7 @@ Sumit Semwal <sumit.semwal@ti.com>
 Tejun Heo <htejun@gmail.com>
 Thomas Graf <tgraf@suug.ch>
 Thomas Pedersen <twp@codeaurora.org>
+Tiezhu Yang <yangtiezhu@loongson.cn> <kernelpatch@126.com>
 Todor Tomov <todor.too@gmail.com> <todor.tomov@linaro.org>
 Tony Luck <tony.luck@intel.com>
 TripleX Chung <xxx.phy@gmail.com> <zhongyu@18mail.cn>