scsi: bsg: Replace zero-length array with flexible array member

Replace the deprecated zero-length array with a modern flexible array
member in the struct iscsi_bsg_host_vendor_reply.

Link: https://github.com/KSPP/linux/issues/78


Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Link: https://lore.kernel.org/r/20241110223323.42772-2-thorsten.blum@linux.dev


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>