Crossport commit ded67782e6d06069873adce7f9074d273ae75760 from 1.4.0

    Plcpi_piix4: fix segfault migrating from 1.2

    b0b873a07872f7ab7f66f259c73fb9dd42aa66a9 bumped the vmstate version and
    introduced an old-style load function to handle migration from prior
    (<= 1.2) versions.

    The load function passes the top-level PIIX4PMState pointer to
    vmstate_load_state() to handle nested structs for APMState and
    pci_status, which leads to corruption of the top-level PIIX4PMState,
    since pointers to the nested structs are expected.

    A segfault can be fairly reliably triggered by migrating from 1.2 and
    issuing a reset, which will trigger a number of QOM operations which
    rely on the now corrupted ObjectClass/Object members.

    Fix this by passing in the expected pointers for vmstate_load_state().

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