vfio/platform: Disable virqfds on cleanup

irqfds for mask and unmask that are not specifically disabled by the
user are leaked.  Remove any irqfds during cleanup

Cc: Eric Auger <eric.auger@redhat.com>
Cc:  <stable@vger.kernel.org>
Fixes: a7fa7c77

 ("vfio/platform: implement IRQ masking/unmasking via an eventfd")
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20240308230557.805580-6-alex.williamson@redhat.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>