cpu/a9mpcore: QOM casting cleanup

Introduce type constant and cast macro and enforce its use by
renaming A9MPPrivState::busdev field to parent_obj.

Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
timer/arm_mptimer: QOM cast cleanup

Introduce type constant and cast macro and rename
ARMMPTimerState::busdev to enforce its use.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>
cpu/a15mpcore: QOM cast cleanup

Introduce type constant and cast macro and rename A15MPPrivState::busdev
field to parent_obj to enforce its use.

Prepares for QOM realize.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>