KVM: arm64: nv: Drop VCPU_HYP_CONTEXT flag

It has become obvious that HCR_EL2.NV serves the exact same use
as VCPU_HYP_CONTEXT, only in an architectural way. So just drop
the flag for good.

Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240419102935.1935571-5-maz@kernel.org


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