Fix driver incorrectly building fcpCdb during scsi command prep (CR 126209)

Fix driver incorrectly building fcpCdb during scsi command prep (CR 126209)

Some scsi inquiry commands were failing with sense key 0x5 and ASC/ASCQ values
of 24/00. At times, this failure cause retries over several hours because the
driver was returning DID_BUS_BUSY. These retries and failures were clogging up
the console logs. Now, always initialize the fcpCdb to 0 during
lpfc_scsi_prep_cmnd. After the memset, only copy scsi_cmnd->cmd_len bytes into
the fcpCdb.

commit id: df9e1b59f9e4671930a7762b9518461df4ea85f5

Signed-off-by: Maxim Uvarov <maxim.uvarov@oracle.com>