cpuset: update MAINTAINERS entry

Add mailing list and tree tag to the entry.
Signed-off-by: NLi Zefan <lizefan@huawei.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

MAINTAINERS

@@ -2408,8 +2408,10 @@ F:	tools/power/cpupower/
 
 CPUSETS
 M:	Li Zefan <lizefan@huawei.com>
+L:	cgroups@vger.kernel.org
 W:	http://www.bullopensource.org/cpuset/
 W:	http://oss.sgi.com/projects/cpusets/
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git
 S:	Maintained
 F:	Documentation/cgroups/cpusets.txt
 F:	include/linux/cpuset.h