hw/cxl/events: Add event status register

hw/cxl/events: Add event status register

The device status register block was defined.  However, there were no
individual registers nor any data wired up.

Define the event status register [CXL 3.0; 8.2.8.3.1] as part of the
device status register block.  Wire up the register and initialize the
event status for each log.

To support CXL 3.0 the version of the device status register block needs
to be 2.  Change the macro to allow for setting the version.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20230530133603.16934-2-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>