[SCSI] sas: add flag for locally attached PHYs

Add a flag to mark a PHY as attached to the HBA as opposed to beeing on
an expander.  This is needed because various features are only supported
on those.  This is a crude hack, the proper fix would be to use
different classes for host-attached vs expander phys.  I'm looking into
that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>