MAINTAINERS: Add myself as SCHED_DEADLINE reviewer

As discussed with Juri and Peter.

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/4476a6da70949913a59dab9aacfbd12162c1fbd7.1599146667.git.bristot@redhat.com