scsi: mpt3sas: Convert to flexible arrays

This converts to a flexible array instead of the old-style 1-element
arrays. The existing code already did the correct math for finding the size
of the resulting flexible array structure, so there is no binary
difference.

The other two structures converted to use flexible arrays appear to have no
users at all.

Link: https://lore.kernel.org/r/20220201223948.1455637-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpi/mpi2_ioc.h

@@ -537,7 +537,7 @@ typedef struct _MPI2_EVENT_NOTIFICATION_REPLY {
 	U16 Event;		/*0x14 */
 	U16 Reserved4;		/*0x16 */
 	U32 EventContext;	/*0x18 */
-	U32 EventData[1];	/*0x1C */
+	U32 EventData[];	/*0x1C */
 } MPI2_EVENT_NOTIFICATION_REPLY, *PTR_MPI2_EVENT_NOTIFICATION_REPLY,
 	Mpi2EventNotificationReply_t,
 	*pMpi2EventNotificationReply_t;
@@ -639,7 +639,7 @@ typedef struct _MPI2_EVENT_DATA_HOST_MESSAGE {
 	U8 Reserved1;		/*0x01 */
 	U16 Reserved2;		/*0x02 */
 	U32 Reserved3;		/*0x04 */
-	U32 HostData[1];	/*0x08 */
+	U32 HostData[];		/*0x08 */
 } MPI2_EVENT_DATA_HOST_MESSAGE, *PTR_MPI2_EVENT_DATA_HOST_MESSAGE,
 	Mpi2EventDataHostMessage_t, *pMpi2EventDataHostMessage_t;
 
@@ -1397,7 +1397,7 @@ typedef struct _MPI2_SEND_HOST_MESSAGE_REQUEST {
 	U32 Reserved8;		/*0x18 */
 	U32 Reserved9;		/*0x1C */
 	U32 Reserved10;		/*0x20 */
-	U32 HostData[1];	/*0x24 */
+	U32 HostData[];		/*0x24 */
 } MPI2_SEND_HOST_MESSAGE_REQUEST,
 	*PTR_MPI2_SEND_HOST_MESSAGE_REQUEST,
 	Mpi2SendHostMessageRequest_t,