scsi: scsi_debug: Fix two typos in command definitions

Fix two command definitions:

 - Flags and service action reversed in SEND DIAGNOSTIC

 - ATOMIC WRITE missing opcode

Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Link: https://lore.kernel.org/r/20250310155557.2872-2-Kai.Makisara@kolumbus.fi


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>