hw/arm/bcm2835: Use object_initialize() on PL011State

hw/arm/bcm2835: Use object_initialize() on PL011State

To be coherent with the other peripherals contained in the
BCM2835PeripheralState structure, directly allocate the PL011State
(instead of using the pl011 uart as a pointer to a SysBusDevice).

Initialize the PL011State with object_initialize() instead of
object_new().

Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <20190507163416[email protected]>
Reviewed-by: Paolo Bonzini <[email protected]>
Reviewed-by: Alistair Francis <[email protected]>
Signed-off-by: Eduardo Habkost <[email protected]>