[README.FSD] Add 'disk_new' entry

Follow-up to 022f4b2 (r55555).

Author: SergeGautherie

media/doc/README.FSD

@@ -20,6 +20,7 @@ The following FSD are shared with: https://github.com/Microsoft/Windows-driver-s
 
 drivers/filesystems/cdfs            # Synced to f73e552
 drivers/filesystems/fastfat_new     # Synced to 2817004
+drivers/storage/class/disk_new      # Forked. (Imported on 2012.01.26 (r55211, from Windows XP DDK), merged to trunk on 2012.02.12 (r55555).)
 drivers/storage/floppy_new          # Synced to 8fb512a
 
 The following FSD are shared with: ??? ('nfs41 project'. See CORE-8204.)