scsi: mpi3mr: struct mpi3_sas_io_unit_page1: Replace 1-element array with flexible array

Replace the deprecated[1] use of a 1-element array in struct
mpi3_sas_io_unit_page1 with a modern flexible array.

No binary differences are present after this conversion.

Link: https://github.com/KSPP/linux/issues/79

 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20240711155637.3757036-4-kees@kernel.org


Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>