zswap: add Vitaly to the maintainers list

Per conversation with Dan, add myself to the zswap MAINTAINERS list.

Link: http://lkml.kernel.org/r/20191028143154.31304-1-vitaly.wool@konsulko.com
Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
Acked-by: Dan Streetman <ddstreet@ieee.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>