In the presence of SOS, ACRN uses fallback_iommu_domain which is the same
used by SOS, to assign domain to devices during ACRN init. Also it uses
fallback_iommu_domain when DM requests ACRN to remove device from UOS domain.
This patch changes the design of assign/remove_iommu_device to avoid the
concept of fallback_iommu_domain and its setup. This way ACRN can commonly
treat pre-launched VMs bringup w.r.t. IOMMU domain creation.
Tracked-On: #2965
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>