This commit adds support for the following emulated hard disks:
HD30 30 MB CDC Wren 94155-36
HD72 73 MB CDC Wren II 94156-86
HD72C 72 MB Fujitsu M2243AS
HD135 161 MB Maxtor XT1190
This commit improves the integrated disk (ID) controller's behavior,
enabling full support for up to two 72MB (emulated WREN II)
integrated winchester disks.