scsi: qla2xxx: Fix DMA error when the DIF sg buffer crosses 4GB boundary

When SGE buffer containing DIF information crosses 4G boundary, it results
in DMA error. This patch fixes this issue by calculating SGE buffer size
and if it crosses 4G boundary, driver will split it into multiple SGE
buffers to avoid DMA error.

Signed-off-by: Giridhar Malavali <gmalavali@marvell.com>
Signed-off-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>