hw/core/clock-vmstate: define a vmstate entry for clock state

hw/core/clock-vmstate: define a vmstate entry for clock state

Signed-off-by: Damien Hedde <[email protected]>
Reviewed-by: Peter Maydell <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Reviewed-by: Edgar E. Iglesias <[email protected]>
Message-id: 20200406135251[email protected]
Signed-off-by: Peter Maydell <[email protected]>