hpsa: use scsi host_no as hpsa controller number

Rather than numbering the hpsa controllers with an
incrementing 0..n value (e.g., that shows up in
/proc/interrupts), use the scsi midlayer
host_no (e.g. matching /sys/class/scsi_host/hostNN).

Reviewed-by: Scott Teel <scott.teel@pmcs.com>
Reviewed-by: Kevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Reviewed-by: Hannes Reinecke <hare@Suse.de>
Signed-off-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Don Brace <don.brace@pmcs.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>