commit 1699490d upstream.

If an expander reports 'PHY VACANT' for a phy index prior to the one
that generated a BCN libsas fails rediscovery.  Since a vacant phy is
defined as a valid phy index that will never have an attached device
just continue the search.
Signed-off-by: Thomas Jackson <thomas.p.jackson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>