virtio-blk: Remove duplicate property definition

virtio-blk: Remove duplicate property definition

For the virtio-blk device (via virtio-pci) the property "config-wce" is
defined in two places.  First, it's defined from the
DEFINE_VIRTIO_BLK_FEATURES macro, second it's defined directly in
virtio-pci, just two lines above the call to that macro.

The direct definition in virtio-pci.c is broken, since it operates on the
'config_wce' field of VirtIOBlkConf, which is never used anywhere else.
Therefore, this patch removes both the extra property definition and the
redundant field it works on.

Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Cc: Paul 'Rusty' Russell <rusty@rustcorp.com.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>