KVM: arm/arm64: vgic-its: Add MSI-LPI translation cache invalidation

There's a number of cases where we need to invalidate the caching
of translations, so let's add basic support for that.

Tested-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>