KVM: arm64: nv: Truely enable nXS TLBI operations

KVM: arm64: nv: Truely enable nXS TLBI operations

Although we now have support for nXS-flavoured TLBI instructions,
we still don't expose the feature to the guest thanks to a mixture
of misleading comment and use of a bunch of magic values.

Fix the comment and correctly express the masking of LS64, which
is enough to expose nXS to the world. Not that anyone cares...

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240703154743.824824-1-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>