This adds support for memory(pc-dimm) hot remove on arm/virt that
uses acpi ged device.

NVDIMM hot removal is not yet supported.
Signed-off-by: NShameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Message-id: 20200622124157.20360-1-shameerali.kolothum.thodi@huawei.com
Reviewed-by: NEric Auger <eric.auger@redhat.com>
Tested-by: NEric Auger <eric.auger@redhat.com>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>