ofdisk: add a comment about vscsi method

grub-core/disk/ieee1275/ofdisk.c

@@ -228,6 +228,9 @@ dev_iterate (const struct grub_ieee1275_devalias *alias)
       if (grub_ieee1275_open (alias->path, &ihandle))
 	return;
 
+      /* This method doesn't need memory allocation for the table. Open
+         firmware takes care of all memory management and the result table
+         stays in memory and is never freed. */
       INIT_IEEE1275_COMMON (&args.common, "call-method", 2, 3);
       args.method = (grub_ieee1275_cell_t) "vscsi-report-luns";
       args.ihandle = ihandle;