iommu/ipmmu-vmsa: Drop IOVA cookie management

The core code bakes its own cookies now.

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/dc5513293942d81f84edf61b354b236e5ac51dc2.1628682048.git.robin.murphy@arm.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>