MAINTAINERS: add Roman as a memcg co-maintainer

Add myself as a memcg co-maintainer.  My primary focus over last few
years was the kernel memory accounting stack, but I do work on some
other parts of the memory controller as well.

Link: https://lkml.kernel.org/r/20220221233951.659048-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: rgushchin

MAINTAINERS

@@ -4914,6 +4914,7 @@ CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)
 M:	Johannes Weiner <hannes@cmpxchg.org>
 M:	Michal Hocko <mhocko@kernel.org>
 M:	Vladimir Davydov <vdavydov.dev@gmail.com>
+M:	Roman Gushchin <roman.gushchin@linux.dev>
 L:	cgroups@vger.kernel.org
 L:	linux-mm@kvack.org
 S:	Maintained