KVM: arm64: nv: Advertise support for PAuth

Now that we (hopefully) correctly handle ERETAx, drop the masking
of the PAuth feature (something that was not even complete, as
APA3 and AGA3 were still exposed).

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-15-maz@kernel.org


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