KVM: selftests: arm64: Add support for various modes with 16kB page size

The 16kB page size is not a popular choice, due to only a few CPUs
actually implementing support for it. However, it can lead to some
interesting performance improvements given the right uarch choices.

Add support for this page size for various PA/VA combinations.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Link: https://lore.kernel.org/r/20211227124809.1335409-7-maz@kernel.org