scsi: 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: KSPP#78
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>

include/scsi/scsi_bsg_iscsi.h

@@ -59,7 +59,7 @@ struct iscsi_bsg_host_vendor {
  */
 struct iscsi_bsg_host_vendor_reply {
 	/* start of vendor response area */
-	uint32_t vendor_rsp[0];
+	uint32_t vendor_rsp[];
 };