Following the previous patches, where vmxnet3's pci's msi/msix
capability offsets and msix's PBA table offsets have been changed, this
patch introduces a boolean property 'x-old-msi-offsets' to vmxnet3,
whose default is false.
Setting 'x-old-msi-offsets' to 'on' preserves the old offsets behavior,
which allows migration to older versions.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com> Signed-off-by: Jason Wang <jasowang@redhat.com>