scsi: qla2xxx: Add fix to read correct register value for ISP82xx.

Add fix to read correct register value for ISP82xx, during check for
register disconnect.ISP82xx has different base register.

Fixes: a465537a ("qla2xxx: Disable the adapter and skip error recovery in case of register disconnect")
Signed-off-by: Sawan Chandak <sawan.chandak@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>