staging: unisys: remove virtpci driver from staging tree

The virtpci driver is being rewritten, so remove the driver from the staging
tree.

Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>