scsi: mpi3mr: struct mpi3_event_data_sas_topology_change_list: Replace 1-element array with flexible array

Replace the deprecated[1] use of a 1-element array in struct
mpi3_event_data_sas_topology_change_list with a modern flexible array.

Additionally add __counted_by annotation since phy_entry is only ever
accessed in loops controlled by num_entries. For example:

        for (i = 0; i < event_data->num_entries; i++) {
		...
                handle = le16_to_cpu(event_data->phy_entry[i].attached_dev_handle);

No binary differences are present after this conversion.

Link: KSPP#79 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20240711155637.3757036-1-kees@kernel.org
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: kees

drivers/scsi/mpi3mr/mpi/mpi30_ioc.h

@@ -453,9 +453,6 @@ struct mpi3_event_data_sas_notify_primitive {
 #define MPI3_EVENT_NOTIFY_PRIMITIVE_POWER_LOSS_EXPECTED   (0x02)
 #define MPI3_EVENT_NOTIFY_PRIMITIVE_RESERVED1             (0x03)
 #define MPI3_EVENT_NOTIFY_PRIMITIVE_RESERVED2             (0x04)
-#ifndef MPI3_EVENT_SAS_TOPO_PHY_COUNT
-#define MPI3_EVENT_SAS_TOPO_PHY_COUNT           (1)
-#endif
 struct mpi3_event_sas_topo_phy_entry {
 	__le16             attached_dev_handle;
 	u8                 link_rate;
@@ -496,7 +493,7 @@ struct mpi3_event_data_sas_topology_change_list {
 	u8                                 start_phy_num;
 	u8                                 exp_status;
 	u8                                 io_unit_port;
-	struct mpi3_event_sas_topo_phy_entry   phy_entry[MPI3_EVENT_SAS_TOPO_PHY_COUNT];
+	struct mpi3_event_sas_topo_phy_entry   phy_entry[] __counted_by(num_entries);
 };
 
 #define MPI3_EVENT_SAS_TOPO_ES_NO_EXPANDER              (0x00)