MAINTAINERS: Orphan vfio fsl-mc bus driver

Email to Diana is bouncing.  I've reached out through other channels
but not been successful for a couple months.  Lore shows no email from
Diana for approximately 18 months.  Mark this driver as orphaned.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20240401170224.3700774-1-alex.williamson@redhat.com


Signed-off-by: Alex Williamson <alex.williamson@redhat.com>