scsi: mpt3sas: Make MPI2_CONFIG_PAGE_SASIOUNIT_0::PhyData[] a flexible array

This terminal 1-length variable array can be directly converted into a C99
flexible array member.

As all users of MPI2_CONFIG_PAGE_SASIOUNIT_0 (Mpi2SasIOUnitPage0_t) either
calculate its size without depending on its sizeof() or do not use
PhyData[], no further source changes are required:

 - mpt3sas_config.c:mpt3sas_config_get_number_hba_phys() fetches a
   Mpi2SasIOUnitPage0_t for itself, but does not use PhyData[].

 - mpt3sas_config.c:mpt3sas_config_get_sas_iounit_pg0() fetches a
   Mpi2SasIOUnitPage0_t into a caller-provided buffer, and may fetch and
   write PhyData[] into that buffer depending on its sz argument.  Its
   callers:

   - mpt3sas_scsih.c:_scsih_update_vphys_after_reset(),
     mpt3sas_scsih.c:_scsih_get_port_table_after_reset(),
     mpt3sas_scsih.c:_scsih_sas_host_refresh(),
     mpt3sas_scsih.c:_scsih_sas_host_add(), and
     mpt3sas_transport.c:_transport_phy_enable() all calculate sz
     independently of sizeof(Mpi2SasIOUnitPage0_t) and allocate a
     suitable buffer before calling mpt3sas_config_get_sas_iounit_pg0()
     and using PhyData[].
Signed-off-by: James Seo <james@equiv.tech>
Link: https://lore.kernel.org/r/20230806170604.16143-5-james@equiv.techTested-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h

@@ -2178,12 +2178,9 @@ typedef struct _MPI2_SAS_IO_UNIT0_PHY_DATA {
 	*pMpi2SasIOUnit0PhyData_t;
 
 /*
- *Host code (drivers, BIOS, utilities, etc.) should leave this define set to
- *one and check the value returned for NumPhys at runtime.
+ *Host code (drivers, BIOS, utilities, etc.) should check the value returned
+ *for NumPhys at runtime before using PhyData[].
  */
-#ifndef MPI2_SAS_IOUNIT0_PHY_MAX
-#define MPI2_SAS_IOUNIT0_PHY_MAX        (1)
-#endif
 
 typedef struct _MPI2_CONFIG_PAGE_SASIOUNIT_0 {
 	MPI2_CONFIG_EXTENDED_PAGE_HEADER    Header;   /*0x00 */
@@ -2191,8 +2188,7 @@ typedef struct _MPI2_CONFIG_PAGE_SASIOUNIT_0 {
 	U8                                  NumPhys;  /*0x0C */
 	U8                                  Reserved2;/*0x0D */
 	U16                                 Reserved3;/*0x0E */
-	MPI2_SAS_IO_UNIT0_PHY_DATA
-		PhyData[MPI2_SAS_IOUNIT0_PHY_MAX];    /*0x10 */
+	MPI2_SAS_IO_UNIT0_PHY_DATA          PhyData[];/*0x10 */
 } MPI2_CONFIG_PAGE_SASIOUNIT_0,
 	*PTR_MPI2_CONFIG_PAGE_SASIOUNIT_0,
 	Mpi2SasIOUnitPage0_t, *pMpi2SasIOUnitPage0_t;