MAINTAINERS: mark CAIF as orphan

The listed address for the CAIF maintainer bounces with
"553 5.3.0 <dmitry.tarnyagin@lockless.no>... No such user here", and the
only existing email address of the maintainer in git history hasn't
responded in a week.
Therefore, remove the listed maintainer and mark CAIF as orphan.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>