MAINTAINERS: Add trace-events and qemu-option-trace.texi to tracing section

MAINTAINERS: Add trace-events and qemu-option-trace.texi to tracing section

The "trace-events" and "qemu-option-trace.texi" files in the top directory
are currently "unmaintained" according to scripts/get_maintainer.pl. They
obviously belong to the Tracing section, so add an entry for them there.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 1525840700-30635-1-git-send-email-thuth@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>