Setting the 'fallback' property corrupts the QOM instance state
(FDCtrlSysBus) because it accesses an incorrect offset (it uses
the offset of the FDCtrlISABus state).
Cc: qemu-stable@nongnu.org
Fixes: a73275dd6fc ("fdc: Add fallback option")
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210407133742.1680424-1-f4bug@amsat.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>