scsi: mpt3sas: Display message before releasing diag buffer

Display message before releasing the diag buffer so that user knows which
event caused the release of diag buffer.

Releasing of diag buffer means HBA firmware stops posting the firmware logs
on the registered diag buffer.

Link: https://lore.kernel.org/r/1568379890-18347-3-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>