KVM: arm64: vgic-its: Rip out the global translation cache

The MSI injection fast path has been transitioned away from the global
translation cache. Rip it out.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240422200158.2606761-12-oliver.upton@linux.dev


Signed-off-by: Marc Zyngier <maz@kernel.org>