scsi: mpt3sas: Disable DIF when prot_mask set to zero

scsi: mpt3sas: Disable DIF when prot_mask set to zero

By default DIF Type 1, DIF Type 2 & DIF Type 3 will be enabled.  Also,
users can enable either DIF Type 1 or DIF Type 2 or DIF Type 3 or in any
combination using the prot_mask module parameter.

However, when the user provides a prot_mask module parameter value of zero,
then the driver is not disabling the DIF. Instead it enables all three
types.

Modify the driver to disable the DIF support if the user provides a
prot_mask module parameter value of zero.

Link: https://lore.kernel.org/r/1588065902-2726-1-git-send-email-sreekanth.reddy@broadcom.com
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>