cgroup: update MAINTAINERS entry

Update my email address.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

MAINTAINERS

@@ -1940,7 +1940,7 @@ F:	drivers/connector/
 
 CONTROL GROUPS (CGROUPS)
 M:	Tejun Heo <tj@kernel.org>
-M:	Li Zefan <lizf@cn.fujitsu.com>
+M:	Li Zefan <lizefan@huawei.com>
 L:	containers@lists.linux-foundation.org
 L:	cgroups@vger.kernel.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git