This patch saves the device table entries into guest RAM.
Both flat table and 2 stage tables are supported. DeviceId
indexing is used.

For each device listed in the device table, we also save
the translation table using the vgic_its_save/restore_itt
routines. Those functions will be implemented in a subsequent
patch.

On restore, devices are re-allocated and their itt are
re-built.
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: NChristoffer Dall <cdall@linaro.org>