scsi: smartpqi: Replace one-element arrays with flexible-array members

One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element arrays with flexible-array
members in a couple of structures, and refactor the rest of the code,
accordingly.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines
on memcpy().

This results in no differences in binary output.

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/204


Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/ZJNdKDkuRbFZpASS@work


Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>