vfio-pci: Fix remove path locking
vfio-pci: Fix remove path locking

Locking both the remove() and release() path results in a deadlock
that should have been obvious.  To fix this we can get and hold the
vfio_device reference as we evaluate whether to do a bus/slot reset.
This will automatically block any remove() calls, allowing us to
remove the explict lock.  Fixes 61d792562b53.

Signed-off-by: Alex Williamson <7469de9b95ba379e2656fa9677689657c47a7690@redhat.com>
Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@vger.kernel.org	[3.17]

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs