maintainers: update maintainers list for vfio-user & multi-process QEMU

Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

MAINTAINERS

@@ -3786,7 +3786,6 @@ F: tests/tcg/aarch64/system/semiheap.c
 Multi-process QEMU
 M: Elena Ufimtseva <elena.ufimtseva@oracle.com>
 M: Jagannathan Raman <jag.raman@oracle.com>
-M: John G Johnson <john.g.johnson@oracle.com>
 S: Maintained
 F: docs/devel/multi-process.rst
 F: docs/system/multi-process.rst