[SCSI] libsas: Fix incorrect sas_port deformation in sas_form_port

[SCSI] libsas: Fix incorrect sas_port deformation in sas_form_port

Currently, sas_form_port checks the given asd_sas_phy's sas_phy to see if
there's already a port attached.  If so, the SAS addresses of the port and
the phy are compared to determine if we need to detach from the port
because the addresses don't match or if we can stop; the SAS address stored
in the sas_port reflects whatever device _was_ attached to the port/phy, and
the SAS address stored in the sas_port reflects whatever device we just
discovered.  As written, the code detaches from the port if the addresses
_do_ match, and prints an error if they do _not_ match.  I believe this to
be incorrect, as it seems more logical to keep the port if the addresses
match (i.e. the phy was reset but the device didn't change), and detach it
they do not (i.e. the device changed).

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>