pds_core: delete VF dev on reset

When the VF is hit with a reset, remove the aux device in
the prepare for reset and try to restore it after the reset.
The userland mechanics will need to recover and rebuild whatever
uses the device afterwards.

Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>