scsi: mpt3sas: Fix trace buffer registration failed

The ExtendedType field was set to 1 in the diag buffer register command and
hence MPT Endpoint firmware is failing the request with Invalid Field
IOCStatus.

memset the request frame to zero before framing the diag buffer register
command.

Link: https://lore.kernel.org/r/20220825075457.16422-3-sreekanth.reddy@broadcom.com


Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>